distribution of community water systems across the...
TRANSCRIPT
October 1996 R.B.96-17
DISTRIBUTION OF COMMUNITY WATER SYSTEMS
ACROSS THE UNITED STATES WITH EMPHASIS ON
SIZE, WATER PRODUCTION, OWNERSHIP, AND
TREATMENT
by
Richard N. Boisvert
and
Todd M. Schmit
Department of Agricultural, Resource, and Managerial Economics College of Agricultural and Life Sciences
Cornell University
Ithaca, New York 14853-7801
It is the Policy of Comell University actively to support equality
of educational and employment opportunity. No person shall be
denied admission to any educational program or activity or be
denied employment on the basis of any legally prohibited
discrimination involving, but not limited to, such factors as race,
color, creed, religion, national or ethnic origin, sex, age or
handicap. The University is committed to the maintenance of
affirmative action programs which will assure the continuation of •such equality of opportunity.
DISTRIBUTION OF COMMUNITY WATER SYSTEMS ACROSS THE UNITED
STATES WITH EMPHASIS ON SIZE, WATER PRODUCTION, OWNERSHIP, AND
TREATMENT
by
Richard N. Boisvert and Todd M. Schmit
ABSTRACT*
An understanding of the diversity of community water systems (CWS) in the United States
is essential when evaluating the financial implications of the 1986 and subsequent amendments to
the Safe Drinking Water Act (SDWA). This diversity, in terms of size, primary water source,
ownership, and existing levels of treatment, shape the nature of the technical, institutional, and
financial issues that must be confronted in moving these systems toward compliance with SDWA
regulations. This report provides a descriptive summary of these operating and design
characteristics ofCWS's across the country.
The data are organized to help provide a typology of representative public water systems
that can be examined to better understand the regional effects of policy implementation. The focus
of the analysis is on small water systems, those most burdened by the expanded montoring and
treatment regulations; much of the data are also provided for larger systems for purposes of
comparison and completeness.
Emphasis is directed towards current water treatment objectives being pursued by CWS's
and the treatment processes already in place. It is for those smaller systems that may require the
addition of multiple water treatment processes that the financial implications are likely to be most
severe.
As would be expected, there is a shortfall between the number of systems serving fewer
than 10,000 people employing multiple treatment processes and the estimated number required.
There are systems, however, that have demonstrated success with a number of multiple treatment
processes, particularly in the small and medium-size categories. The experience gained by these
systems would seem invaluable in efforts to accelerate the process of field testing and approval of
technologies applicable to systems serving lower population levels.
-• The authors are Professor and Research Support Specialist, respectively, in the Department of Agricultural, Resource, and Managerial Economics, Cornell University. Partial funding was provided by the Agricultural Policy Branch, Office of Policy Analysis and Evaluation, United States Environmental Protection Agency. The findings and opinions expressed here are those of the authors and not necessarily those of the EPA.
Table of Contents
INTRODUCTION 1
PUBLIC WATER SYSTEMS DEFINED 3
TIlE FEDERAL REPORTING DATA SYSTEM 4
A NATIONAL AND REGIONAL PERSPECTIVE .,... 6
Distribution of CWS' s by Population Served 6 System Size as Measured by Flow or Design Capacity 10 System Ownership 14 Treatment Objectives 17
Treatment Objectives 21 Treatment Processes 24
POLICY INIPLICATION AND CONCLUSIONS 32
REFERENCES 36
APPENDIX A 38
APPENDIX B 47
APPENDIX C 57
APPENDIX D 61
APPENDIX E 66
APPENDIX F 69
APPENDIX G 75
AITACHMENT 1 77
AITACHMENT 2 94
-
List of Tables
1. Distribution of Community Water Systems and Population Served by Ground and Surface Water Sources 7
2. Per Capita Average Daily Flow and Design Capacity by Population Category 12
3. Per Capita Average Daily Flow and Design Capacity Distributions by Water Source and Population Classification 13
4. Ownership Type Percentage Distributions by Water Source and Population Classification 16
5. General Treatment Objectives of All Community Water Systems 22
6. Multiple Treatment Objectives Found in Very Small Community Water Systems 25
7. Multiple Treatment Objectives Found in Small Community Water Systems .. 26
8. Estimated and Actual Treatment Combinations Used by Community Water Systems 28
9. Relative Short Fall Between Estimated Treatment Needs and Actual Treatment Combinations Used by CWS's with a Ground Water Source 30
10. Relative Short Fall Between Estimated Treatment Needs and Actual Treatment Combinations Used by CWS's with a Surface Water Source 31
AI. Data for Kolmogorov-Smimov Test of Size Distributions of All Community Water Systems .. 40
.A2. Data for Kolmogorov-Smimov Test of Size Distributions for Ground Water Systems 41
A3. Data for Kolmogorov-Smimov Test of Size Distributions for Surface Water Systems 42
A4. Kolmogorov Test Statistics and Results of Hypothesis Tests 44
List of Tables (continued)
B1. Percentage Distribution of Community Water Systems by System Size 49
B2. Percentage of Population Served by Community Water Systems by System Size 50
B3. Average Water Production and Design Capacity of Community Water Systems : 51
B4. Percentage Distribution of Community Water Systems by Ownership 53
B5. Percentage Distribution of Community Water Systems by Treatment Classification 53
B6. Percentage Distribution of the Number of Community Water Systems by Water Source 54
B7. Percentage Distribution of the Water Production by Community Water Systems by Water Source 55
C1. Variables for Regressions on Average Daily Flow and Design Capacity 57
C2. Regression Equations for Average Daily Flow and Design Capacity 59
01. General Treatment Objectives of Very Small Community Water Systems 61
02. General Treatment Objectives of Small Community Water Systems 62
03. General Treatment Objectives of Medium Community Water Systems 63
04. General Treatment Objectives of Large Community Water Systems 64
05. General Treatment Objectives of Very Large Community Water Systems 65
E1. Multiple Treatment Objectives Found in Medium Community Water Systems 66
E2. Multiple Treatment Objectives Found in Large Community Water Systems 67
E3. Multiple Treatment Objectives Found in Very Large Community Water Systems 68
List of Tables (continued)
Fl. Multiple Treatment Processes Found in Very Small Community Water Systems 70
F2. Multiple Treatment Processes Found in Small Community Water Systems 71
F3. Multiple Treatment Processes Found in Medium Community Water Systems ~ 72
F4. Multiple Treatment Processes Found in Large Community Water Systems 73
F5. Multiple Treatment Processes Found in Very Large Community Water Systems 74
G1. Estimated Treatment Needs and Actual Treatment Combinations Used by Community Water Systems with a Ground Water Source 75
G2. Estimated Treatment Needs and Actual Treatment Combinations Used by Community Water Systems with a Surface Water Source 76
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List of Figure
1. Community Water System Distribution by System and Population Served by Size Category.. 8
List of Exhibits
1. Combined Treatment Objective and Process Codes 19
B1. EPA Regions, Regional Office Location, and States Included 48
Fl. Codes for Water Treatment Processes 69
-
INTRODUCTION
As part of a comprehensive examination of the status of our nation's community water
systems (CWS) and the financial implications of the 1986 Amendments to the Safe Drinking
Water Act (SDWA), one must have a clear picture of the number and diversity of these
systems both nationally and at the regional level. This diversity, particularly in terms of size,
primary water source, ownership, and existing levels of treatment, shape the nature of the
technical, institutional, and financial issues that must be confronted in moving the nation's
many community water systems toward compliance with SDWA regulations. I
The purpose of this report is to provide a descriptive summary of these various
operating and design characteristics of CWS's across the country. As such, the manuscript is
one of the first in a series designed to provide a comprehensive look at the implications of the
1986 amendments. The objectives are modest relative to the scope of the overall research
effort, but they are a necessary first step. Emphasis is focused on the policy implications that
can be drawn from a careful analysis of the data. These data are also organized to help
provide a typology of representative public water systems that can be examined to better
understand the regional effects of policy implementation. The focus of the analysis is on small
water systems, but much of the data is also provided for larger systems primarily for purposes
of comparison and completeness.
Brief summaries of the size distribution of public water systems are already contained
In two previous reports designed to assess the benefits and costs of the 1986 SDWA
amendments, and the technical and economic capacity of states and public water systems for
implementation of the 1986 amendments (Wade Miller Associates, 1990, and EPA, 1993).
However, the assessments in these reports focused primarily at the national level, and there was
little need to articulate differences in the distribution of systems regionally or by characteristics
such as ownership, system capacity, and nature of the population served. At the time at least
one of these studies was completed, many of the rules associated with various provisions of
the 1986 amendments were at best in the early stages of development; few systems had yet to
be confronted with the reality of compliance, so there was little need to focus on existing
monitoring and treatment experience.
Passage of the 1996 amendments to the SDWA (PL-I04-182) occurred during the development of this report. As such, the predominant focus of the report is directed towards the 1986 amendments, application is made to the 1996 amendments where appropriate. Given the descriptive nature of this report, this should be of little concern.
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2
The issues surrounding the implementation of the 1986 amendments go well beyond
those related to aggregate benefits and costs to society, which are the primary bases for
justifying the regulations from a national perspective. Knowledge of the diversity of systems
at a more disaggregate level is essential for the examination of these broader issues. For
example, detailed information about public water systems at the regional level should be of
interest in the design and location of regional centers for technical assistance as authorized in
the 1996 amendments to the Safe Drinking Water Act. To the extent that the distribution of
systems by type differs regionally, the cost of compliance relative to the benefits will differ as
well. This could alter the financial implications for local governments, and in regions where
the perceived benefit-cost ratios are lowest, the incentives for seeking exemptions could be
quite high. The potential for viable restructuring could also be affected. Information
concerning the proportion of systems owned privately and their size may be important to
understand the effects of new legislative initiatives such as the unfunded mandate legislation
passed recently by both the Senate and the House. This could be particularly true if, as some
suspect, the availability of exemptions from full compliance would differ between public and
private providers. Information about the type of population served by community water
systems should enable one to make educated guesses about the income distribution in order to
study the financial effects of amendments on individuals by income class.
The remainder of the report is divided into several sections. To provide a clear picture
of what the data represent, we begin by reiterating the definition of a public water system.
Since the data described in this report come primarily from the FRDS-II Data Base, we also
discuss briefly how the data were organized to complete the analysis, and how potential
problems associated with missing data in this large data base were handled. The focus then
shifts to a discussion of the characteristics of water systems at the national level and their
policy implications. The policy significance of the regional diversity of water systems is also
highlighted? Perhaps the most important section relates to the current treatment objectives
and levels of treatment. This discussion helps to delineate the treatment needs, but it also
provides a good indication of what financially feasible treatment strategies are being used
currently by large and small systems. It should be invaluable in establishing priorities for
further research. The final section summarizes the conclusions and implications for policy.
Before proceeding, it is also important to emphasize that the nature of the analysis requires the
presentation of a lot of data, particularly relating to the treatment strategies. This makes for
2 To facilitate this discussion of the regional data without adding unduly to the length of the text of the report, a detailed description of the regional diversity of water systems and the supporting data is included in an appendix. Its primary purpose is as a source document for those interested in the specific regional data.
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some rather tedious reading at times, but we offer few apologies because this is very much a
working document; much of the descriptive analysis is designed to help set priorities for further
research.
PUBLIC WATER SYSTEMS DEFINED
A public water system (PWS), according to the definition used by the Federal
government for policy purposes, is one that pipes water to the public for human consumption
(EPA, 1993). To qualify as a PWS, a system must have at least 15 service connections, or
regularly serve at least 25 individuals for two months or more during the year. By federal
definition, PWS's are further divided into two groups: community water systems and non
community water systems. Non-community water systems are either transient or non-transient.
Of the more than 200 thousand PWS's across the nation, nearly 30% are community water
systems (CWS), just over 10% are non-transient, non-community systems (NTNC), and the
remaining systems, nearly 60%, are transient, non-community systems (TNC).
In addition to being descriptive of the types of customers they serve, these
classifications are important because the extent to which they must comply with the 1986
amendments differs. Historically, for example, all non-community water systems were required
to meet only those standards designed to prevent short-term health problems such as bacteria,
nitrates, and turbidity. This remains true for most transient, non-community systems (such as
campgrounds, motels, and gas stations) which cater to transient customers in non-residential
areas. The estimated 3% of these systems that rely on surface water supplies are also required
to meet standards for filtration and disinfection (EPA, 1993).
On the other hand, non-transient non-community water systems must serve at least 25
people at least six months of the year and include schools, factories, hospitals and other
institutions with their own water supplies. Subsequent to their passage, NTNC's are required
to comply with the 1986 SDWA amendments. This is also true for community water systems
(CWS), defined as public water systems which serve at least 15 service connections used by
year-round residents or regularly serve at least 25 year-round residents. CWS' s range from
smaller units such as trailer parks and housing complexes to larger systems serving rural and
suburban communities and large cities. Since the majority of systems which are potentially
affected most seriously by the passage of the 1986 SDWA amendments are community water
systems, the analysis here focuses on this group. This is consistent with the analysis in EPA's recent report to Congress on the technical and economic capacity of states and public water
systems to implement drinking water regulations (EPA, 1993).
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THE FEDERAL REPORTING DATA SYSTEM
The data on CWS's analyzed in this report come primarily from EPA's FRDS-II Data
Base as of July 1, 1994. The data base is designed specifically to support the EPA's Office
of Groundwater and Drinking Water (OGWDW) in monitoring compliance with the Safe
Drinking Water Act of 1974. Water systems across the country are required to report
information about their systems on an annual basis to their respective state agencies, who, in
turn, forward it to the FRDS system maintained at EPA's computing center in North Carolina.
The FRDS-II Data Base is a complex data structure for public water systems arranged
hierarchically in four levels and containing information relating to the operation, design, and
treatment. There is detailed information on: population served, daily water production and
design capacity, ownership, primary water sources, treatment objectives, treatment processes
employed, the geographic areas served, on site visits and water sampling, violation and
enforcement actions, and variance/exemption actions. As one moves deeper into the hierarchy
of the system, it is necessary to maintain numerous records for each system. For example, the
source/entry file in Level 2 contains individual records for each water source utilized by a
particular CWS listed in the Levell file. The treatment data file, located in Level 3, contains
separate records for each treatment process that is linked to each source record from Level 2.
The location of the treatment (i.e., at the source, treatment plant, or entry point) is also attached
to these records. 3
This type of data structure lends itself well to retrieving complete data for one or a
handful of systems. However, the structure presents a real challenge to anyone attempting to
use such a data base for research purposes where detailed data on all systems must be
summarized and analyzed. To our knowledge, no one has attempted such an analysis, and to
this extent, much of the information in this report is not widely known.
This report relies primarily on the first-and second-level descriptive features of CWS's
across the country relating to operation characteristics, production requirements, and treatment
processes and objectives. Subsequent reports will concentrate more on types and frequencies
of violation and enforcement actions and/or variances related to those violations.
3 Other data files exhibit a similar "branching" structure, such as the non-compliance file at Level 2 which branches first into the violation file at Level 3, and second into the file on enforcement action at Level 4. Put differently, a CWS listed in Level 1 may be flagged as being non-compliant at Level 2, with the one or more individual violations associated with non-compliance delineated at Level 3. Each of these records is finally linked to the one or more enforcement actions in Level 4 associated with the corresponding violation contained in Level 3 records.
5
In any data base of this size and where reporting is ultimately the responsibility of
individuals at the system level, there are always some problems with the data. To facilitate the
identification of these problems and the manipulation of the data, we converted the entire
FRDS-II Data Base into SAS data files. For this analysis, we focused attention on systems
located in the 50 states, ignoring, at least for the time being, about 700 systems in the several
territories of the United States.
To obtain a usable data set for this analysis, it was also necessary to eliminate
observations in which important pieces of data were either missing or obviously in error. To
begin, we eliminated observations where some of the most basic information on population
served, ownership, and treatment classification was missing. We also eliminated systems
where the information was provided, but was obviously erroneous because of inconsistencies
between population served, average daily production and design capacity. The result was a
data set including information on about 45,600 community water systems.
Although this is a significant subset of the data (containing 80% of the community
water systems around the country), we were concerned that inferences drawn from it may be
biased if the subset turned out not to be representative of the population. To obtain some
notion of the nature of any bias, we performed a number of statistical tests between the
distribution of the subset of systems by size category and the entire population of water
systems by size category as reported in the EPA's report to Congress on the technical and
economic capacity of states and public water systems to implement drinking water regulations
(EPA, 1993). The test for the similarity of distributions is the Kolmogorov-Smirnov test, and
the results are reported in detail in appendix A.
Based on this test, there is reason to believe that the size distribution of the systems in
the subset is representative of that for the entire population of combined ground and surface
water systems. The same is true for ground water systems examined separately. For surface
water systems, the size distributions appear identical, with the exception of those in the
smallest size category. Here, there seemed to be a slightly higher proportion of small systems
eliminated because of missing or inconsistent data. On this basis, it seems unlikely that the
steps required to develop a useable set of data for the analysis lead to any serious bias in the
results, particularly if one believes that the general characteristics of very small systems are
likely to be more homogeneous than those of systems with retail service populations greater
than 500. -
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A NATIONAL AND REGIONAL PERSPECTIVE
To obtain a picture of the diversity of community water systems from a national
perspective, it is convenient to begin by examining the distribution of systems by size. Size,
however, can be defined in a variety of ways, ranging from the size of the population served,
to some measure of the average (or peak) daily flow or the system's design capacity. Measures
of average daily flow or design capacity are most important for decisions regarding water
system construction and water treatment, and are related to the population served, but not
completely so.' The demand for water also depends among other things on climate, the
demographic makeup of the population, as well as the nature of the retail, industrial, and
residential development in the service area.
For policy purposes and to facilitate the development of regulations, the EPA groups J
public water systems into 12 categories by size of population served if the information
necessary to formulate the regulation is available at that level of detail (EPA, 1993). Where
information is limited, the systems are recombined into five size categories which are simple
aggregations of the initial 12. These categories are defined according to the population served,
and are presented in table 1.
Classifying systems in this way for policy purposes is one way to focus attention on the
potential resources that can be drawn on to meet the costs of compliance with the SDWA
regulations. For example, it is generally believed that systems serving populations of 10,000
or more are large enough to take advantage of economies of size in production and
management and sufficient resources to finance increased monitoring and treatment at a
reasonable cost to customers. For systems serving fewer people, the possibilities for realizing
economies of size in production, distribution, or planning are limited, and the ability to finance
needed treatment and monitoring to comply with SDWA regulations is more problematic.
Other characteristics such as ownership of the system and the primary water source affect the
cost, as well as the resources available to comply with the regulations.
Distribution of cws 's by Population Served
Of the more than 57,000 community water systems nationwide, just over 18% of them
rely on surface water as their primary water source, with the remaining 82% relying primarily
on ground water. The data in table I provide a clear picture of the distribution of CWS' s by
population size category for all systems, as well as for groups differentiated by whether the
system's primary water source is from ground or surface water. These data are easier to
,
!
),,
)
Table 1. Distribution of Community Water Systems and Population Served by Ground and Surface Water Sources.
Population Population Population Category Range Classification
A
B < 101
101 to 500 I > Very Small
C 501 to 1,000
D 1,001 to 2,500 Small
E 2,501 to 3,300
F
G
3,301 to 5,000
5,001 to 10,000
Medium
H I
J
10,001 to 50,000
50,001 to 75,000
75,001 to 100,000
Large
K > 100,000 ~ Very Large
Ground and Surface
Water Systems
Population Number Served
29.6 0.4
31.0 1.9
10.8 1.9
12.0 4.6
3.1 2.2
3.3 3.2
4.2 7.3
4.7 24.7
0.5 6.8
0.2 4.2
0.5 42.9
Ground Water Surface Water
Systems Systems
Population Population Number Served Number Served
%--------
34.6 1.0 7.5 0.0
33.6 4.1 19.6 0.4
10.6 3.8 11.5 0.7
10.4 8.3 19.0 2.3
2.4 3.4 6.3 1.3
2.3 4.6 7.6 2.2
2.8 9.9 10.6 5.4
2.8 29.3 13.6 21.6
0.2 6.9 1.5 6.8
0.1 4.5 0.7 4.0
0.2 24.1 2.1 55.2
I
-.....l
3,301 10,000
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Figure 1. CWS Distribution by System and Population Served by Size Category.
70% 60.7%
60% 42.9%Q) 50%
0[) ell 40%...... c Q) u 30% .... Q)
~ 20% i I10%
-+__10 J
0%
Less 501 10,001 Over than 501 3,300 100,000 100,000 /
System Population Category -------_._ ._---~
'_II System Percentage • Population Percentage --- ------- ... _------. ------------.-- -
visualize in figure 1. Very small systems, those serving retail populations of less than 500
people, account for the lion's share (over 60%) of all CWS's nationwide. Given their size, it
is not surprising that they serve only an estimated 2% of the population. Small systems, those
serving between 501 and 3,300 people, account for an additional 26% of all systems and serve
just under 9% of the retail population. Medium-sized systems, serving retail populations
between 3,301 and 10,000 people, constitute slightly more than 7% of all CWS's, and serve
an additional 10% of the retail population. The remaining 80% of the population is served by
only 6% of the CWS's, all of which have a service population of more than 10,000; within this
group, over 40% of the population is served by the one-half of one percent of the CWS's with
a service population over 100,000.
The fact that such a large percentage of the population is served by large systems with
sufficient resources to take advantage of economies of size in water treatment and system
administration tends to disguise the magnitude of the problems in achieving greater compliance
with the 1986 amendments to the Safe Drinking Water Act. While only 10% of the population
is affected, the unique problems facing small systems potentially affect about 50,000 CWS's
and/or units of local government distributed across the country, somewhat differentially by
region as is seen in the data from appendix B.
For example, the proportion of small and very small systems exceeds the national 'average significantly in New England and in the three EPA regions served by Dallas, Denver,
and Seattle. The proportion of the population served by these systems in the Dallas region is
more than double the national average. With the exception of the metropolitan areas
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surrounding the regional offices in these latter two regions, the small systems are scattered
across the sparsely populated areas of the northern plains where population densities are among
the lowest in the country. In New England, the rural populations served by these small
systems are much more evenly distributed across the landscape. Thus, the problems facing
small systems in these two diverse areas, and the potential for restructuring in terms of physical
consolidation or administrative cooperation can be expected to be markedly different.
Perhaps one of the few bright spots about the nature of small water systems affecting
their effort to expand water treatment is their relatively large reliance on ground water as the
primary source of water. Nearly 92% of all ground water systems are in the small and very
small categories, and they serve over 20% percent of the population receiving water from
ground water sources (table 1). Part of the explanation lies in the fact that many of the areas
served by these small systems have no proximity to a surface water source, and, in other cases,
the source development costs could have been lower than that for surface water or the quality
of the raw water could have been higher. 4
Regardless of the reasons for this pattern, there are important implications for
compliance with the SDWA regulations and modifications in them that might be anticipated
in future reauthorization efforts. The most direct implication relates to the Surface Water
Treatment Rule (SWTR). This rule was promulgated in June of 1989 and requires surface
water sources to apply disinfection and may require filtration unless specific criteria are met.
These requirements are designed to protect against the adverse health effects associated with
various viruses, heterotrophic bacteria, and other pathogenic organisms (54 FR 27486).
With the exception of those ground water sources under the direct influence of surface
water, none of these rules apply to small or very small systems whose primary source is
ground water. Fortunately, according to the data in FRDS-II, fewer than two-tenths of one
percent of the ground water systems are under the direct influence of surface water.
In addition, the Information Collection Rule (ICR) defines specific monitoring
requirements based on a system's size. Systems subject to the SWTR and serving populations
of more than 10,000 or ground water systems serving more than 50,000 are all affected by the
ICR. All utilities serving more than 100,000 people must develop a formal sampling plan,
including monthly monitoring requirements for coliphage viruses and Clostridium perfringens,
as well as traditional coliforms, Giardia, and Cryptospiridium. The smaller systems will be ,
4 Although small surface water systems serve less than 5% of the population receiving water from surface water sources, they still represent nearly 65% of all surface water systems.
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required to monitor every two months; all subject to change relative to microbes to be tested
and testing schedules. It is expected that monitoring for disinfection by-products (DBP) will
proceed in a parallel fashion, with EPA looking for chemicals of concern related to chloramine,
chlorine, dioxide, and ozone disinfection. ..
In additon to a more relaxed standard setting process from the 1996 amendments to the
SDWA, small water system monitoring requirements will be limited to those contaminants
likely to be detected in their drinking water. EPA must issue regulations for a monitoring
program regarding unregulated contaminants. These regulations ensure that only a
representative sample of small water systems witll be required to monitor for all regulated
contaminants. States with primacy may provide interim monitoring relief for PWS' s serving
under 10,000 people. However, systems must provide to customers annual reports on existing
contaminant levels and potential health effects.
Furthermore, where the raw water from a ground water source is of high quality, small
water systems may benefit from a growing recognition that the list of potentially effective
strategies for insuring the safety of our drinking water extend well beyond conventional
treatment solutions, including a greater emphasis on watershed planning and the identification
of methods for adequate source protection.
System Size as Measured by Flow or Design Capacity
Although for many purposes it makes sense to classify CWS' s by the population served,
measures of size that are more directly related to the actual volume of water produced are also
important for planning purposes and projecting system costs. Classifying systems by these
measures is less important for policy purposes, but given the availability of data on average
daily flow and design capacity, it is useful to relate these three measures of size directly in a
formal mathematical way. In so doing, we essentially are able to estimate two equations
econometrically that provide estimates of conditional demands for water at the system level. 5
Demands can easily be put on a per capita basis.
5 We refer to conditional demand models in much the same way energy economists have used multivariate regression models with demographic characteristics, weather, and the stock of household appliances to estimate electricity consumption or appliance util ization rates (EPRI EA-3410, 1984, and Parti and Parti, 1980). Tn this case, however, the regression models are used to estimate average daily flow or design capacity as functions of population served, weather, and geographic location. These consumption estimates are conditional in the sense that the effect of price cannot be determined because of the lack of data. To the extent that there are systematic differences in price by region or in rural vs. urban areas, the dummy variables in the regression may reflect some of the price differentials.
11
These relationships will prove extremely useful in further research, but it should be
pointed out that in working with the FDRS-II Data Base the quality of the data on a system's
average daily flow and system design capacity was perhaps the most problematic. In many
cases, only one of the two variables was reported, and in other cases both were missing.
Therefore, in addition to their being useful in other research, these equations were necessary
to estimate missing values for many systems in order to develop size distributions of CWS's
using these variables as measures of size. To estimate the conditional demand relations, we
used data from over 11,000 systems for which there was reliable data on these variables. The
estimated equations are given in appendix C, along with a detailed discussion of the
interpretation of the estimated coefficients.
As one would expect, both the average daily flow and the design capacity of water
systems are positively related to the population served as well as the number of hookups. The
design capacity is also positively related to the average daily flow, requiring that the two
equations be estimated in a two-stage fashion. These equations are used to estimate the
average daily flow and the design capacity for all the systems in the data set for which data
were mIssmg.
Based on these estimates, the mean average daily flow (production) (ADF) is about
700,000 gallons per day; the design capacity is just under 1.9 million gallons per day. This is
about 2.7 times the average daily production, and the excess capacity is there partly to
accommodate peak flows and to anticipate growth in demand or system expansion.
On a per capita basis, average daily flow is estimated at about 126 gallons per day
(table 2). This figure is understandably larger than the per capita consumption implied by the
300-gallon per day estimate of household indoor use for a typical family of four (EPA, 1991).
On a per capita basis, these estimated average daily flows are remarkably consistent across
systems by population category. The many additional demands placed on a water system in
urban areas for industrial, commercial, institutional, and emergency purposes certainly explains
why per capita demands placed on the very large systems are nearly 40% higher than for the
very small systems. The 138 gallon average daily flow per person for the smallest group is
larger than for systems serving populations between 101 and 10,000, probably because of some
need for systems to be of some minimum size to operate properly. Water needs for
emergencies, etc. also constitute a disproportionate share of total production for these very
small systems.
12
Table 2. Per Capita Average Daily Flow and Design Capacity by Population Category.
Average Daily Flow Design Capacity Population Population Per Capita Per Capita
Category Range Mean Std. Dev. Mean Std. Dev.
All Categories A-K 126 113 789 692
A < 101 138 III 1,232 786 B 101 to 500 118 123 774 652
C 501 to 1,000 113 114 551 486 D 1,001 to 2,500 119 112 480 411 E 2,501 to 3,300 123 104 440 403
F 3,301 to 5,000 127 107 408 339 G 5,001 to 10,000 130 108 391 310
H 10,001 to 50,000 139 76 379 292 I 50,001 to 75,000 155 62 385 250
J 75,001 to 100,000 164 62 431 288
K > 100,000 181 77 431 277
Note: Average flow and capacity values are given in gallons per day per capita.
The variation around the mean in average daily flow is substantial for all systems, but
is higher for the small and medium-size systems. The same pattern is evident in the variation
in design capacity. This variation is certainly due in large measure to the socioeconomic and
demographic characteristics of the service areas, and without detailed data on the demographic
structure of the population and the diversity of the economic systems it is impossible to sort
the differences out precisely.
However, by examining the coefficients on the dummy variables in the regression
equations in appendix C, we do see part of the explanation. All else equal, the design capacity
tends to be higher in the hot and semi-arid areas in the South and the West, and in urban areas.
Compared with systems that serve non-residential areas, systems that serve residential and
semi-residential areas design systems with smaller capacities for a given service population.
Design capacities of private systems tend to be smaller than for those owned by the
government. The capacity also tends to be smaller for systems that purchase water from other
systems or rely primarily on surface rather than ground water. The story is about the same for
the equation used to predict average daily flow. The two exceptions are: the average daily 'flow is higher for surface water systems than for ground water systems (table 3), and average
daily flow is also higher if the system serves a semi-residential area. These trends are certainly
evident in the regional data reported in appendix B.
--
Table 3. Per Capita Average Daily Flow and Design Capacity Distributions by Water Source and Population Classification.
Ground Water Systems Surface Water Systems
Population Average Daily Flow Design Capacity Average Daily Flow Design Capacity
Classification Mean Std. Dev. Mean Std. Dev Mean Std. Dev. Mean Std. Dev
All Populations 125 112 863 717 131 121 434 431
Very Small 128 116 1027 763 127 133 669 588
w Small 115 109 542 471 122 121 398 337
Medium 124 86 437 326 134 130 349 312
Large 132 57 421 278 150 86 346 294
Very Large 171 73 506 318 185 79 399 252
Note: Average flow and capacity mean values are expressed in gallons per day per capita.
I
14
The explanation for why the design capacities of ground water systems tend to have
larger design capacities but smaller average daily flows than for surface water systems is
straightforward if viewed in terms of the financial and other requirements to expand or
otherwise change the two types of systems. Increasing production for a given surface water
system may, in many instances, require modest changes such as increasing intake flow rates
from an established reservoir or impoundment. The situation, however, may be much more
complicated for a ground water system. The physical and technical changes could very well
include the drilling of additional wells, the installation of additional transmission mains, or
increased storage capacity. Therefore, to allow for possible growth in demand and avoid the
additional costs of increasing capacity in the future, it may be more cost effective to "oversize"
the systems to some degree in the initial construction phase.
System Ownership
During the debate over re-authorization, it was clear that members of both Houses of
Congress were keenly aware of the financial burden facing the owners of small water systems
throughout the country as they make changes to comply with the SDWA, and it is their hope
that this financial burden can be eased by careful relaxation of some requirements without
seriously compromising water quality or health risk. The 1996 amendments to the SDWA
provide additional federal funding for drinking water system improvements in the form of a
state revolving loan fund (SRF), similar in form to the current SRF available in the Clean
Water Act for waste water treatment improvements. The fund provides $9.6 billion in grant
and loan funding, capitalized over the years of 1994 through 2003, for local water system
facility improvments. To ease the burden further, the 1996 amendments provide to states up
to 15% of annual funding for PWS' s serving less than 10,000 people. In addition, states may
use up to 30% of theire fund allocation for special assistance to small, disadvantaged systems.
The appropriateness of the size of this set aside turns not only on the size distribution
of water systems across the country, but on the distribution of ownership as well. The
importance of the size distribution is perhaps the most obvious. While 15% of the funds are
earmarked for systems serving populations below 10,000, we know from the data above, that
these community water systems constitute over 90% of the total and provide water to about
20% of the population (table 1). Clearly, funds are not being set aside in proportion to the
number of systems or population served. It is unclear at this time whether the cost savings
provided by the relief from some of the regulations are sufficient to offset the higher costs of
compliance with the remaining provisions. It is well known that these small systems are
15
unable to take advantage of the substantial economies of size in water supply and treatment
(Boisvert and Tsao, 1995).
If it turns out that funds are insufficient, then the effects will be largest in EPA regions
where the proportions of population served by systems of less than 10,000 are well above the
national average (See table B2). These include regions whose regional offices are located in
Dallas, Kansas City, Denver, and Seattle. The situation could well be exacerbated in these
regions, as well as throughout the country if, as is suspected by many, the infrastructure of
many small systems has been allowed to deteriorate. In such cases, EPA estimates that for
every dollar spent on treatment there would be need for an additional dollar spent on
rehabilitation and repair (EPA, 1993).
The implications of system ownership for the requirements for allocating money from
the revolving funds are less clear until one remembers that money from these funds are
earmarked primarily for public/governmental water systems, with some provisions for investor
owned (private) water systems. Public water systems not owned by a governmental or inter
governmental agency, a non-profit organization, an Indian tribe, or any combination thereof,
may receive assistance from a state revolving fund; however it will be designated only to those
systems having the greatest public health and financial needs. Granted, the specification here
is vague and determining those systems with the "greatest" need may be obligatory, but, it is
also clear that owners of private systems may be at a competitive disadvantage in applying for
these loan funds.
This is unlikely to be a trivial problem because only 41 % of all CWS' s are owned by
local governments, including authorities, commissions, districts, municipalities, cities, towns,
and counties, while 53% are owned privately by various entities such as subdivisions, investors,
trusts, cooperatives, and water associations (table 4).6
These ownership patterns are not overly surprising, based on the high proportion of
small systems, most of which are located in smaller communities or mobile home parks and
housing complexes. Over 96% of the systems serve primary residential areas, of which 17%
of them serve mobile home parks. This is certainly reflected as well in the distribution of
ownership by system size. About 73% of the very small systems are owned privately,
-6 Ownership of the remaining CWS's is in the hands of the Federal government (1%), the state
governments (I %), mixed public and private ownership (4%), and Native Americans (less than one-half of 1%). The Native American classification includes indian tribes and reservations and Alaskan remote villages.
Table 4. Ownership Type Percentage Distributions by Water Source and Population Classification.
Population
Classification
Ground and Surface Water Systems
Local Private Government
Ground Water Systems
Local
Private Government
Surface Water Systems
Local Private Government
- - - - - - -% - - - - - - - - - - - - - -
All Populations 52.6 41.2 59.7 33.9 20.3 66.4
Very Small 72.9 20.9 75.9 17.9 39.3 55.7 -0',
Small 25.4 67.7 28.5 64.6 16.4 76.6
Medium 12.5 81.7 15.4 78.1 8.7 86.3
Large 13.3 82.5 16.9 77.0 10.2 87.3
Very Large 20.1 78.3 21.6 73.0 19.4 80.6
Note: The percentage of systems not accounted for are owned by Federal and state governments, mixed public and private
entities, and Native American villages.
, .. ~ .... ~ '. -- ._.. _-.... --_._...,-_.-~ ~ -,..
17
dropping to just over 25% in the small system category. From a regional perspective, the
proportion of private ownership is much higher than the national average in New England and
in the EPA regions served by regional offices in New York, Philadelphia, and Atlanta (table
B4). The predominance of private ownership in these regions is explained in part by the fact
that they were the oldest developed areas of the country and by the fact that the desire for local
control is as strong in New England and the Northeast as any where in the country. The nature
of the retirement communities in Florida may also partially explain this trend in the Atlanta
regIOn.
One can only speculate on the average income levels of the people living in areas
served by these small private water systems. In some cases where the systems serve exclusive
developments and upper middle income multi-family housing developments, we know the
answer. We probably also know the answer for those that serve mobile home parks and
similar developments, and it is here where low-income people and others on fixed incomes will
have the most difficulty absorbing the additional costs of treatment passed on by the owners
of the private systems. The incomes of rural residents is generally lower than those of their
suburban and urban counterparts as well (EPA, 1988; Boisvert and Ranney, 1991). How these
considerations are factored into plans for allocating money from revolving funds have
important implications for equity.
Again, the only bright spot in this scenario is that nearly 60% of the ground water
systems are privately owned. In contrast, local governments own nearly 75% of the surface
water systems, and to the extent that the treatment needs of these systems are likely to be more
extensive than for ground water systems, there may be some justification for a disproportionate
share of revolving fund loans to go to these systems.
Treatment Objectives
In attempting to deal with the particular problems facing smaller community water
systems, the 1996 amendments to the SDWA also contain provisions for making the
regulations more flexible and less costly for states and local governments, including relaxing
the schedules for testing and monitoring for contaminants. Specifically, the amendments
contain provisions for communities serving fewer than 10,000 people to use alternative, more
affordable technologies to meet current and anticipated drinking water regulations. These
alternatives, referred to as Best Available Affordable Technologies (BAAT), are to be designed by EPA and may include public education and notification. The BAAT' s may not reduce
18
contaminant levels to regulated MCL' s, but the level of treatment is to be sufficient so as not
to result in an unreasonable health risk.
An important step in understanding the effects of legislation is to know the treatment
practices and treatment objectives currently in place in the Nation's medium-sized and small
community water systems. This will provide a perspective of the seriousness of the remaining
problems and also lend perspective on treatment practices that seem to be working for a
selected number of systems. This will be a solid foundation for examining the economic
feasibility of adapting these successful treatment scenarios to other systems.
Dealing with treatment objectives and the individual processes used to meet the various
objectives is undoubtedly the most complex aspect of the FRDS-II Data Base. Exhibit 1
provides some perspective on the long list of the most relevant treatment processes and the
corresponding treatment objectives that can be met by each. A comprehensive examination of
these data is complicated by at least two factors. The first is rather mechanical, and relates to
those systems for which treatment information is from the previous FRDS' s data file
(FRDS1.5). This indicates that treatment for these systems has not changed recently. It
appears that the earlier version of FRDS 's did not differentiate between treatment processes and
objectives, and while one can infer treatment objectives from the process file, there is no way
to obtain this information from the treatment objective file. Therefore, for our purposes these
records are eliminated from initial consideration. As is seen below, this causes few problems.
The second complexity is a direct result of the fact that some water systems have more
than one water source and/or plant.. Since treatments can differ by source and plant, the
treatment file can contain multiple records for an individual system. Developing a strategy for
summarizing the data under these conditions was a challenge. It was extremely difficult to
avoid double counting etc.
We were assisted In our efforts by a variable in FRDS-II that is generated by the
program which classifies CWS's as treated, mixed, or untreated. A "treated" classification
implies that all of a particular system's water sources are subjected to treatment; an "untreated"
classification implies that none of a particular system's water sources are subjected to
treatment. Obviously, a system is assigned a "mixed" treatment classification when systems
with multiple water sources provide treatment for water from at least one source, but no
treatment for water from at least one other source. Regardless of whether the system is ,.classified as "treated" or "mixed", the treatment objectives for water at each source may well
differ. Water can be treated at the source, at the treatment plant, or at the point of entry.
--
--
---
Exhibit I. Combined Treatment Objective & Process Codes
Treatment Objectives
DBP Corrosion Dis- De- In- Man- Par· Radio- Taste/
Treatment Process Control Control infection Chlorination Iron organics ganese Organics ticulate nuclides Soften Ordor
Activated Alumina X X
X X XActivated Carbon, Granular X X X
XActivated Carbon, Powder X X
X X XAeration, Cascade X X X
X X XAeration, Diffused X X X
X X XAeration, Packed Tower X X X
X X XAeration, Slat Tray X X X
XAeration, Spray X X XX X
XChlorine Dioxide X
X XCoagulation X X X X
X XX X X XDistillation X
XElectrodialysis X
XFiltration, Cartridge
XDiatomaceous Earth
X XGreensand
XPressure Sand X X X X X
XX X X X XRapid Sand X
X XSlow Sand
XUltrafiltration
XGas. Chlorination, Post
X XGas. Chlorination, Pre X X X
XHypochlorination, Post
XX X X XHypochlorination, Pre
XInhibitor
XIodine
X X XIon Exchange
X XXXLime - Soda Ash
XMicroscreening
XOzonation, Post X
X XX X XOzonation, Pre X
X X XPermanganate
X X XPeroxide
X XReducing Agents
X X XX X XReverse Osmosis X -
XUltraviolet Radiation X
X X X X X XXpH Adjustment X
..... '0
1 I
20
According to this variable, over 60% of CWS's nationwide are classified as "treated"
and, therefore, meet at least one treatment objective for each source. Of the remaining CWS' s,
32% are classified as "untreated", while 7% are "mixed" (table B5 of appendix B). Put
differently, nearly 70% of CWS's provide at least some treatment for their sources of water,
and, irrespective of system size, more systems provide treatment than do not. For systems
serving larger retail populations, there is a larger proportion of them in the "mixed" treatment
category. This seems only logical, since as systems increase in size, the average number of
water sources used increases, providing greater flexibility in treatment options. The fact that
treatment may differ by source could reflect incremental investment in new sources of water . .fto accommodate growth in demand. I I
f As one would expect, the proportions of systems treating at least one of its water .,II
sources increases with system size: 97% of the very large systems are classified as "treated"
or "mixed", while 91 % and 87%, respectively, of the large and medium-size systems fall into
these two categories. Given the heightened concern over the implications for smaller systems
of the 1986 amendments to the SDWA it is perhaps somewhat surprising to see that over 50%
of the small and very small systems are doing some type of treatment. It remains to be seen,
the extent to which these treatment objectives are consistent with the requirements under the
1986 amendments. This can only be done by moving deeper into the details of the treatment
files. In this way, we eventually hope to match treatment objectives with treatment processes
as a way of identifying appropriate treatment technologies for meeting various combinations
of treatment objectives.
The extent to which systems are currently treating water differs by primary water source
as well. About 65% of ground water systems apply at least some treatment; this is
significantly below the 80% of all surface water systems that treat at least some portion of their
raw water. Although smaller ground water well systems are likely to apply no treatment, as
systems serve larger populations, storage with at least some disinfection requirements may be
needed; this is certainly one explanation of why this gap narrows between ground water and
surface water systems as size increases. To provide further insight into the differences in
current treatment practices, we need to examine specific treatment objectives and/or processes
in use and delineate situations where systems are meeting more than one treatment objective.
Multiple treatment objectives and/or treatment processes which address multiple contaminant ,
regulations will have significant impacts on system and national cost-benefit analyses.
21
Treatment Objectives. Through the four panels of data in table 5, we obtain a first
glimpse of the detailed information in the FRDS-II Data Base. Since there are some major
differences in the level of treatment between ground water and surface water systems, we focus
on these two subsets immediately. There are about 6,600 systems in the surface water subset
and nearly 34,500 ground water systems.
The total of the two, about 41,100 systems, is about 4,500 fewer than our original
sample for two reasons. First, about half of the removed observations had to be eliminated
because of missing information. The other half of these systems are not in the data because
they purchase water and the water is treated by the seller. Thus, this treatment is reflected in
the data, but it is in the records for systems selling water.
For purposes of the analysis, it is also necessary to ignore systems whose treatment
classification is still in terms of the old FRDS's system. We have no way to know what
treatment is being applied to these systems. This leaves us with about 6,100 surface water
systems and 30,600 ground water systems in the data set.
With these preliminaries out of the way, we can begin to examine the data. The first
panel in table 5 contains those surface water systems that list a single treatment objective.
There are 25% of these systems that have no treatment at all sources and water plants. Just
over 14% of the systems only disinfect, while processes needed to remove particulates only are
in use by about 3% of the systems.
For the ground water systems, nearly 39% have no treatment at any plant or source,
while about 34% only disinfect, and less than 1% soften water, remove particulates and iron,
and operate corrosion control indirectly. There are just a handful of systems that have other
single treatment objectives.
While the data on single treatments are useful to gain perspective on the extent of
treatment, the panels in table 5 containing data on multiple treatments are potentially more
important for identifying the range of treatment options being used already by small systems.
These data, however, need some explanation. To begin, the sum in the systems column is
much greater than the total number of systems, because every individual water source and plant
where a particular treatment objective is met is reported separately and individual sources or
plants may contain more than one treatment objective. Thus, for example, the "no treatment" row contains all systems (61 % of the total) which have at least one source or plant doing no
treatment. Where these systems have other water sources or plants at which there is treatment,
22
Table 5. General Treatment Objectives of All Community Water Systems'
Single Treatment Multiple Treatments Treatment Objective Obj. Code Systems Percentage Systems Percentage
Surface Water SystemsC
Additional Treatment Elsewhere A 0 0.0 7 0.1 Disinfection By-Product Control B 1 0.0 272 4.5 Corrosion Control C 7 0.1 1,432 23.5 Disinfection D 876 14.4 3,970 65.3 . Dechlorination E 0 0.0 11 0.2
Iron Removal F 4 0.1 519 8.5 Inorganics Removal I 0 0.0 224 3.7 Manganese Removal M 0 0.0 152 2.5 No Treatment b N 1,516 24.9 3,718 61.1 Organics Removal 0 1 0.0 384 6.3
Particulate Removal P 153 2.5 3,137 51.6 Radionuclides Removal R 0 0.0 60 1.0 Softening S 7 0.1 597 9.8 Taste/Odor Control T 1 0.0 916 15.1 Other (Process Fluoridation) Z 5 0.1 1,068 17.6
Ground Water Systemsd
Additional Treatment Elsewhere A 0 0.0 0 0.0 Disinfection By-Product Control B 4 0.0 50 0.2 Corrosion Control C 65 0.2 1,996 6.5 Disinfection D 10,543 34.4 16,769 54.8 Dechlorination E I 0.0 14 0.0
Iron Removal F 109 0.4 2,600 8.5 Inorganics Removal I 13 0.0 221 0.7 Manganese Removal M 7 0.0 667 2.2 No Treatment b N 11,790 38.5 21,007 68.6 Organics Removal 0 7 0.0 423 1.4
Particulate Removal P 79 0.3 887 2.9 Radionuclides Removal R 7 0.0 65 0.2 Softening S 124 0.4 1,183 3.9 Taste/Odor Control T 40 0.1 1,146 3.7 Other (Process Fluoridation) Z 85 0.3 2,212 7.2
• Frequencies exclude those system which apply no treatment themselves, but purchase treated water, since unable to tie specific
treatment objective to water utilized; Le. systems with treatment objective=N (no treatment) and treatment process = 996
(treatment applied by seller).
b For sole treatments, no treatment implies no treatment at all source or plant locations. For the general multiple classification, no
treatment implies that the system applies no treatment to at least one source or plant location and may be in addition to other .. treatments.
,.C total systems = 6,083
d total systems = 30,624
23
they are reported separately under that particular objective. A system with two sources of
water employing different objectives at each would be counted in both objective categories.
The same result would occur for a system meeting two treatment objectives at a single source.
According to this interpretation of the data in table 5, there are just over 60% of the
surface water systems around the country in which at least one water source or plant apply no
water treatment whatsoever; the percentage (69%) is only slightly higher for ground water
systems.7 Similarly, about 65% of the surface water systems disinfect their water, while 52%
remove particulates, and nearly a quarter control for corrosion. Another lO% soften their
water; about 15% treat for taste and odor problems; and about 9% remove iron. Fewer than
5% of the surface water systems have processes in place that meet any of the other treatment
objectives listed in the table. Although the percentage of ground water systems that have no
treatment processes in place somewhere in the system is not substantially higher than for
surface water systems, the multiple treatment strategies used seem to be less complex and focus
mainly around disinfection (55%), iron removal (9%), and corrosion control (7%). Just under
4% of the systems soften their water and treat for taste and odor problems. Similar data for
community water systems by size category are given in appendix D for completeness, but there
is no need to discuss the data in detail.
To gain some perspective on what multiple treatment strategies can be used effectively
and at affordable costs, it is helpful to look behind these numbers and delineate the number of
these systems that meet more than one treatment objective. These objectives mayor may not
be accomplished through a single treatment process, and it is in the data in the treatment
process files that we can shed some light on which combinations of processes seem to be
working currently for small and very small systems. We examine the various combinations
of treatment processes used by the community water systems in a subsequent section.
For completeness, we include a detailed list of the number of systems in EPA's five
aggregate size categories that are meeting any possible combination of treatment objectives as
an attachment to this report. However, as is evident from the attachment, there are an
extremely large number of treatment objective combinations, many of which are given by
fewer than 5 water systems. Therefore, to facilitate discussion, we limit our attention to those
combinations of treatments given by at least 5 systems. (The percentages given in the tables
are based on the whole sample, including systems where the combined treatment objectives are
7Although this "no treatment" percentage is not overly meaningful, the percentages under the various treatment objectives do provide a benchmark measure for the extent to which various treatment objectives are met.
I
24
given by fewer than 5 systems.) The data for very small and small systems are in tables 6 and
7, because systems in these two groups are of primary interest to this analysis. Tables EI
through E3 in appendix E contain data for medium, large, and very large systems.
Somewhat surprisingly, the data in table 6 suggest that a significant number of very
small systems are treating to meet a wide combination of treatment objectives, but as one
would expect, the majority of the systems treat for a single objective. Nearly 73% of the
ground water systems only disinfect, while 30% of the surface water systems do likewise.
Another third of the surface water systems disinfect and treat for particulate removal, and about r3% combine some type of corrosion control. Nearly 12% of the surface water systems only
treat for removal of particulates. Nearly 5% of the very small ground water systems disinfect
and only apply some type of corrosion control, with an additional 1.3% adding an additional
objective to disinfection and corrosion control. About 4% disinfect and remove iron. About
4% combine disinfection with either water softening or taste and odor control. Each of the
many remaining combinations of treatment objectives in place are in at most 1% of the
systems, and for most in much less than 1% of the systems.
The story is not terribly different for the small community water systems (table 7). The
number of treatment objective combinations is somewhat higher primarily because a smaller
proportion of systems do no treatment at all. In addition, there are fewer small surface and
ground water systems that treat for only a single objective such as disinfection. Only 60% of
these ground water systems solely disinfect, while this is true for only 26% of the surface
water systems. An additional 34% of the ground water systems and 50% of the surface water
systems combine disinfection with one or more additional treatment objectives.
Treatment Processes. In trying to understand the nature of current treatment strategies
being used by CWS' s across the country, we must look at the various treatment processes as
well. Appendix F contains estimates of the percentages of systems by size category currently
treating water through a variety of treatment processes. While it is important to include the
information at this level of detail in this report, further discussion of it is probably unnecessary.
What is needed is some way to relate the treatment objectives to treatment processes.
Perhaps the best way to do this is to compare these data with estimates of the
proportions of CWS's that would need particular combinations of water treatment technologies .. to meet the 1986 amendments. These proportions were estimated by Miller (1990) and are
based on probabilities of co-occurrence of various contaminants, and the ability of different
processes to deal with the contaminants. The joint probabilities on which the estimates are
25
Table 6. Multiple Treatment Objectives Found in Very Small Community Water Systems
Treatment Ground Water Systems Surface Water Systems
Objectives' Number Percent Number Percent
BD
C CD
CDF CDFM
10 47
495
51
30
0.10
0.46 4.79
0.49 0.29
8 100
CDFP
CDFS
CDI CDO
CDP
7
5 9
19
6
0.07 0.05
0.09 0.18
006 26 3.25
CDPS
CDPT
CDS
CDST CDT
14
5
5
0.14
0.05
0.05
12
8
150
100
CF CPS
D
DF DFM
6
7506
380 189
0.06
72.70
3.68
183
5 237
6
0.63
29.66
0.75
DFMP
DFMS
DFP
DFPS
DFPT
6 6 33
6 14
006
006
0.32
0.06
0.14
DFS
DFT
DI
DIM
DIS
56 20
25
10
5
0.54
0.19 0.24
0.10
0.05
DM DO
DOP
DOT
DP
64
16
49
109
0.62 016
0.47
106
10
5 262
1.25
0.63
32.79
DPS
DPT
DS
DST
DT
14
10 224
15 239
014
0.10 2.17
0.15
2JI
23
10
7
2.88
1.25
0.88
F FM
FP FS
I
130 21
9 9
15
1.26
0.20
0.09 0.09
0.15
IRS
M
0 P
R
5 19
6 81
7
0.05
0.18
0.06 0.78
0.07 93 11.64 -
S
T
116
32
1.12
0.31
'Each letter in this column represents a particular treatment objective from table 5,
e.g. CD is corrosion control combined with disinfection .
..
26
Table 7. Multiple Treatment Objectives Found in Small Community Water Systems
Treatment Ground Water Systems Surface Water Systems
Objectives' Number Percent Number Percent
BDIOPRS 7 0.46
BDPS 15 0.99
C 25 0.48 10 0.66
CD 343 6.65 31 2.04
CDF 102 1.98
CDFM 26 0.50
CDFO 27 0.52
CDFP 17 0.33 7 0.46 CDFPS 8 0.16
CDFPT 7 0.14 11 0.72
CDFS 1J 0.21
CDFT 5 0.10
CDI 7 0.14
CDO 72 1.40
~.~~ _ ~.._ ?.~.~.3. __ .1..?g 2.?? . CDPS 7 0.14 64 4.21
CDPST 10 0.19 10 0.66
CDS 14 0.27 5 0.33
CDST 5 0.10
CDT 13 0.25
D 3114 60.38 402 26.43
DF 375 7.27 9 0.59
DF! 5 0.10
DFM 90 175 5 0.33
DFMP 5 0.10
DFMS 5 0.10
DFO 6 012
DFP 39 0.76 12 0.79
DFPS 13 0.25 10 0.66
DFPT 11 0.21 26 171
DFS 110 2.13
DFST 10 0.19
DFT 24 0.47
DIP 5 0.10 5 0.33
DM 15 0.29
DO 16 O.3i
DOPT 11 072
DOT 11 0.21
DP 35 0.68 298 19.59
DPS 8 0.16 50 3.29
OPST 13 0.25 7 0.46
OPT 15 0.29 47 309
OS 48 0.93 9 059
OST 14 0.27
m 189 366 12 O.~
F 65 1.26
FM 8 0.16
FS 7 0.14
M 9 0.17
P 6 0.12 123 8.09 -S 44 0.85 0.46
T 8 016
'Each letter in this column represents a particular treatment objective from table 5,
ego CD is corrosion control combined with disinfection.
25
Table 6. Multiple Treatment Objectives Found in Very Small Community Water Systems
Treatment Ground Water Systems Surface Water Systems
Objectives' Number Percent Number Percent
SO 10 0.10
C 47 0.46
CO 495 4.79 8 100
COF 51 0.49
COFM 30 0.29
COFP 7 0.07
CDFS 5 0.05
CDI 9 0.09
COO 19 0.18
COP 6 0.06 26 325
COPS 12 150 COPT 8 1.00
CDS 14 0.14
COST 5 0.05
COT ........._ _ __ __.._._.__.__ 5_-_ 0.05_._.__ _ __-_.._._ _ _._ _._ _.__ _ _ __ _._..CF 6 006
CPS 5 0.63
o 7506 72.70 237 29.66
OF 380 3.68 6 0.75
OFM 189 1.83
OFMP 6 0.06
OFMS 6 0.06
OFP 33 0.32
OFPS 6 0.06
OFPT 14 0.14
OFS 56 0.54
OFT 20 0.19
DI 25 0.24
DIM 10 0.10
DIS 5 0.05
OM 64 0.62
DO 16 0.16
OOP 10 1.25
DOT 49 0.47 5 0.63
OP 109 1.06 262 32.79
OPS 14 0.14 23 2.88
OPT 10 0.10 10 125
OS 224 2.17
OST 15 0.15
OT 239 2.31 7 0.88
F 130 126
FM 21 0.20
FP 9 0.09
FS 9 0.09
I 15 0.15
IRS 5 0.05
M 19 0.18
o 6 0.06
P 81 0.78 93 11.64
R 7 0.07
S 116 I 12
T 32 OJI
'Each letter in this column represents a particular treatment objective from table 5,
e.g. CD is corrosion control combined with disinfection .
..
26
Table 7. Multiple Treatment Objectives Found in Small Community Water Systems
Treatment Ground Water Systems Surface Water Systems
Objectives' Number Percent Number Percent
BOlOPRS
BDPS
C
CD
CDF
25
343
102
0.48
6.65
\.98
7
15
10
31
0.46
0.99
0.66
2.04
CDFM
CDFO
CDFP
CDFPS
CDFPT
26
27
17
8
7
0.50
0.52
0.33
0.16
0.14
7
II
0.46
0.72
CDFS
CDFT
COl
CDO
CDP
II 5
7
72
6
0.21
0.10
0.14
1.40
0.12 130 8.55
CDPS
CDPST
CDS
CDST
CDT
7
10
14
5
13
0.14
0.19
0.27
0.10
0.25
64
10
5
4.21
0.66
0.33
D
DF
DF!
DFM
DFMP
3114
375
5
90
5
60.38
7.27
0.10
1.75
0.10
402
9
5
26.43
0.59
0.33
DFMS
DFO
DFP
DFPS
DFPT
5
6
39
13
11
0.10
0.12
0.76
0.25
0.21
12
10
26
0.79
0.66
1.71
DFS
DFST
DFT
DIP
DM
110
10
24
5
15
2.13
0.19
0.47
0.10
0.29
5 0.33
DO
DOPT
DOT
DP
DPS
16
II 35
8
O.3i
0.21
0.68
0.16
11
298
50
0.72
19.59
3.29
DPST
OPT
OS
DST
DT
13
15
48
14
189
0.25
0.29
0.93
0.27
366
7
47
9
12
0.46
3.09
0.59
0.79
F
FM
FS
M
P
65
8
7
9
6
1.26
0.16
0.14
0.17
0.12 123 8.09
S T
44
8
0.85
016
7 0.46
'Each letter in this column represents a particular treatment objective from table 5.
e.g. CD is corrosion control combined with disinfection.
27
based are first approximations. They are based on the best available data, and they were used
in EPA's assessment of the technical and economic capacity of public water systems to comply
with the 1986 SDWA amendments. 8
To understand how these comparisons are made, we can look at the summary data in
table 8. For example, Miller estimates that to comply with the 1986 amendments, 46% of the
very small ground water systems would need to install multiple treatment processes, while 40%
would need only a single process. About 14% would need no treatment at all. Based on the
FRDS's data, however, 48% of the very small ground water systems currently treat none of
their water, while 42% use a single treatment technology, and only 8% currently employ more
than one treatment process.
Perhaps the most striking features of this table are the rather high estimates of the
systems that require no treatment at all to meet the 1986 amendments to the SDWA,
particularly for the medium to very large systems. This means that the proportion of systems
that will need multiple treatments is correspondingly low. Miller (1990) comments on the
relative size of these proportions and suggests that the probability of needing multiple
treatments, particularly for the larger systems is too low. He argues that the results are driven
by the underlying assumptions about contaminant occurrence, the decision trees built into the
analysis, and the numbers of systems in the various size categories. Unfortunately, he provides
too little information about the procedure for us to unravel the mystery, although we suspect
much of the explanation for the underestimates has to do with the assumption of independence
of co-occurrence of all contaminants. This assumption is hard to rationalize in built up areas
served by large and very large water systems. The independence assumption is probably easier
to justify in areas served by smaller systems. The magnitude of the underestimates of the need
for multiple treatment in these cases is probably smaller. For this reason, one might regard
Miller's (1990) estimates as lower bounds on the proportion of systems needing single or
multiple treatments. The estimates provided by Miller may also be more appropriate for
smaller systems since the recent 1996 amendments to the SDWA allow for more relaxed
monitoring and treatment schedules by systems serving fewer than 10,000 people.
Detailed information about the particular combinations of processes on which table 8
was constructed is given in appendix G. In discussing these data, however, we are less
interested in the percentages themselves than we are the short fall between what is needed and
what is in place at the present time. This can be seen best by examining the relative As data from EPA's on-going needs survey of the Nation's public water systems becomes
available, it will certainly be possible to refine these probability estimates. 8
Table 8. Estimated and Actual Treatment Combinations Used by Community Water Systems
Treatment No. of Very Small Small Medium Large Very Large
Combination Treatments Estimated" Actualb Estimated Actual Estimated Actual Estimated Actual Estimated Actual -------------------------%----------------------
Ground Water:
No Treatment 0 14 48 22 21 24 14 25 7 33
Single Treatment 1 40 42 47 53 47 49 47 33 49 18
Multiple Treatment 2+ 46 8 30 19 30 28 28 39 19 44
N 00
Surface Water:
No Treatment 0 12 49 12 22 15 13 15 12 22 4
Single Treatment 1 45 25 45 27 46 27 47 23 50 28
Multiple Treatment 2+ 41 25 42 48 39 58 38 63 28 67
Note: These data were c:tlculated from Tables G 1. and G2. by summing up the number of systems using no treatment, single treatment, and multiple treatments.
"Estimated percentages were calculated from EPA document, Benefits and Costs of the 1986 Amendments to the SDWA (Wade Miller, 1989).
bActual percentages were obtained fromFRDS multiple treatment data search results.
f l
27
based are first approximations. They are based on the best available data, and they were used
in EPA's assessment of the technical and economic capacity of public water systems to comply
with the 1986 SDWA amendments. 8
To understand how these comparisons are made, we can look at the summary data in
table 8. For example, Miller estimates that to comply with the 1986 amendments, 46% of the
very small ground water systems would need to install multiple treatment processes, while 40%
would need only a single process. About 14% would need no treatment at all. Based on the
FRDS's data, however, 48% of the very small ground water systems currently treat none of
their water, while 42% use a single treatment technology, and only 8% currently employ more
than one treatment process.
Perhaps the most striking features of this table are the rather high estimates of the
systems that require no treatment at all to meet the 1986 amendments to the SDWA,
particularly for the medium to very large systems. This means that the proportion of systems
that will need multiple treatments is correspondingly low. Miller (1990) comments on the
relative size of these proportions and suggests that the probability of needing multiple
treatments, particularly for the larger systems is too low. He argues that the results are driven
by the underlying assumptions about contaminant occurrence, the decision trees built into the
analysis, and the numbers of systems in the various size categories. Unfortunately, he provides
too little information about the procedure for us to unravel the mystery, although we suspect
much of the explanation for the underestimates has to do with the assumption of independence
of co-occurrence of all contaminants. This assumption is hard to rationalize in built up areas
served by large and very large water systems. The independence assumption is probably easier
to justify in areas served by smaller systems. The magnitude of the underestimates of the need
for multiple treatment in these cases is probably smaller. For this reason, one might regard
Miller's (1990) estimates as lower bounds on the proportion of systems needing single or
multiple treatments. The estimates provided by Miller may also be more appropriate for
smaller systems since the recent 1996 amendments to the SDWA allow for more relaxed
monitoring and treatment schedules by systems serving fewer than 10,000 people.
Detailed information about the particular combinations of processes on which table 8
was constructed is given in appendix G. In discussing these data, however, we are less
interested in the percentages themselves than we are the short fall between what is needed and
what is in place at the present time. This can be seen best by examining the relative 8 As data from EPA's on-going needs survey of the Nation's public water systems becomes
available, it will certainly be possible to refine these probability estimates.
Table 8. Estimated and Actual Treatment Combinations Used by Community Water Systems
Treatment No. of Very Small Small Medium Large Very Large
Combination Treatments Estimated" Actualb Estimated Actual Estimated Actual Estimated Actual Estimated Actual -------------------------%----------------------
Ground Water:
No Treatment 0 14 48 22 21 24 14 25 7 33
Single Treatment I 40 42 47 53 47 49 47 33 49 18
Multiple Treatment 2+ 46 8 30 19 30 28 28 39 19 44
tv 00
Surface Water:
No Treatment 0 12 49 12 22 15 13 15 12 22 4
Single Treatment I 45 25 45 27 46 27 47 23 50 28
MUltiple Treatment 2+ 41 25 42 48 39 58 38 63 28 67
Note: These data were calculated from Tables GLand G2. by summing up the number of systems using no treatment, single treatment, and multiple treatments.
"Estimated percentages were calculated from EPA document, Benefits and Costs of the 1986 Amendments to the SDWA (Wade Miller, 1989).
bActual percentages were obtained from 'FRDS multiple treatment data search results.
f'"
29
differences between the actual and the estimated percentages of single and multiple treatment
needs (tables 9 and 10), although the conclusions drawn from the sign on these differences is
somewhat ambiguous. For example, if this difference is positive, as is the case for the "no
treatment" percentages, then a move toward more complete compliance would require a
reduction in the actual percentage of systems not treating, while the percentage of systems
employing single or multiple treatments could both rise. In this instance, the interpretation of
the positive difference is straightforward. On the other hand, if the difference is positive for
the single treatment case, it could mean that many of the systems are in compliance, but it
could also imply that many of the systems now using a single treatment actually belong in
multiple treatment category and, therefore, need to install additional treatment processes to be
in compliance with the SDWA amendments.
Despite this ambiguity, when the difference between the actual and estimated percentage
IS negative, more systems belong in that category. Thus, we have a criterion for setting
priorities for study of the economic and institutional feasibility of various combinations of
treatments. Beginning in the multiple treatment category, we can place some priority on those
combinations of processes where the short fall is negative. Highest priority should perhaps be
given where the absolute value of this short fall is the largest. Next on the list of priorities
would be an examination of the single treatments where the negative short fall is highest.
Although the data in tables 9 and 10 provide, in theory, a good criterion by which to
set priorities for the development and evaluation of multiple treatment options, the data
themselves are a bit disappointing. That is, in order to establish clear priorities, one would
have hoped for more variation in the estimated short falls, across treatment combinations and
system size categories. Most of the estimated short falls for the multiple treatment
combinations for the three smallest size groups range between -1.0 and -0.8. A value of -1.0
is important because even though it was estimated earlier that there would be need for systems
to employ these combinations, none have done so to date. A value between -1.0 and 0.0
means that some systems are employing the treatment combination, but not in proportion to
the projected need.
We do, however, see some important patterns in the data. For example, there is
complete consistency across ground water systems with respect to the exclusive use of
corrosion control: no systems currently control corrosion as their only treatment strategy, but
it is an integral part of many of the treatment combinations currently in use. The same is true for activated carbon processes, although only a few systems are now using the multiple
technologies for which this process is an integral part of the projected needs.
30
Table 9. Relative Short Fall Between Estimated Treatment Needs and Actual Treatment Combinations Used by CWS's with a Ground Water Source Treatment No. of Very Small Small Medium Large Very Large
Combination Treatments Relative Short Fall Relative Short Fall Relative Short Fall Relative Short Fall Relative Short Fall ~ % -
No Treatment 0 2.4 -0.1 -0.4 -0.7 -1.0
Alt. Treatment' I 5.0 12.2
Disinfection (DSF)d
Corrosion Control (CC)' fIon Exchange (IE)
I
I
I
2.9
-1.0
-0.2
6.7
-1.0
-0.9
8.7
-1.0
-1.0
ILl
-1.0
-1.0
-1.0
-1.0
Aeration (PTA)'
Gran. Act. Carbon (GAC)h DSF ICC DSF I IE DSF/PTA
I
I 2 2 2
-0.9
~1.0
-0.8 1.5
-0.6
-0.7
-1.0 -0.2 1.3
3.9
-0.7
-1.0
0.4 1.5 10.6
-0.6
-1.0
2.2 1.3
37.5
-1.0
DSF/GAC CCIIE CCIPTA CC/GAC lEI PTA
2 2 2 2 2
-0.9 -1.0 -1.0 -1.0 -1.0
-0.7
-1.0 -0.9 -1.0 -0.8
-0.5 -1.0 -0.9
-0.9 -0.8
-1.0 -0.9 -0.9 -1.0
-1.0
-1.0
IE/GAC PTA/GAC DSF ICCIIE DSF I CC I PTA DSF I CC IGAC
2 2 3 3 3
-0.9 -1.0 -0.8 -0.9 -0.9
-1.0 -1.0 -0.6 0.9 -0.7
-1.0 -1.0 0.1 4.9 0.0
0.2 26.8 7.2
DSF IIE/GAC DSF I lEI PTA DSF I PTA I GAC
3 3 3 -1.0 -0.4
DSF I PTA lIE CC lIE I PTA
3 3 -1.0 -0.9 -1.0 -1.0
CCIIE/GAC
CC/PTA/GAC
-1.0 -1.0
-1.0 -1.0
-1.0 -1.0 -1.0
IE/PTA/GAC DSF I CC lIE I PTA DSF I CC I IE I GAC DSF ICC I PTA I GAC
Other Combinations,
3 4 4 4
-0.9 -0.8
-0.8
0.8 -0.5
-0.9
5.1
-1.0 -1.0 -06
Note: These data were calculated from Table G I by subtracting the actual proportion of systems using a specific combination of treatment options by the estimated proportion of systems needing that combination. This result is divided by the estimated proportion.
'Estimated percentages were calculated from EPA document, Benefits and Costs of the 1986 Amendments to the SDWA (Wade Miller, 1989).
hActual percentages were obtained from FRDS multiple treatment data search results.
'The number of systems using alternative treatments includes those that do not directly affect SDWA treatment reqUirements, (e.g. tluoride treatment).
dDisinfection (DSF) includes treatment process codes C, 0, and U. (See Exhibit Fl.)
'Corrosion (CC) control includes treatment process codes I, H, L. (See Exhibit Fl.)
'Ion exchange (IE) relates to code E, and includes activated both alumina, and anion and cation exchange.
'Aeration (PTA) includes all aeration processes: Cascade, diffused, packed tower, slat spray, and spray aeration.
hGAC includes both powdered and granulated activated carbon processes.
'This category includes treatment combinations that are not considered feasible and combinations estimated to affect less than one percent of all systems.
jAn' • , occurs wherever the estimated value was zero, in which case there would have been a division by zero. -
31
Table 10. Relative Short Fall Between Estimated Treatment Needs and Actual Treatment Combinations Used by CWS's with a Surface Water Source Treatment
Combination
No. of
Treatments
Very Small
Relative Short Fall
Small
Relative Short Fall
Medium
Relative Short Fall
Large
Relative Short Fall
Very Large
Relative Short Fall
No Treatment 0 3.2 0.8 -0.1 -0.2 -0.8
Alt. Treatment' 1 -0.4 3.8
Filtration (FILT)d
Corrosion Control (CC)e
Ion Exchange (IE/
I
I
1
0.0 -1.0
-0.1 -0.8
-0.2
-0.7
-0.3
-0.8 0.4
-0.9
Aeration (PTA)g
Gran. Act. Carbon (GAC)h
FILT/CC FILT lIE
FlLT/PTA
1
1
2 2
2
-0.5
-0.9
0.3
-0.5
-0.6
5.2
-06
-0.4 -0.3
-0.5 -0.2
FlLT/GAC
CCIIE 2 2
0.4 -0.5
1.8 3.0 3.6
CC/PTA
CC/GAC
IE / PTA
2
2
2
-0.9 -0.9 -0.1 0.2
IE/GAC PTA/GAC
FILT / CC lIE FlLT / CC / PTA
FlLT / CC / GAC
2
2
3
3 3
-1.0
0.3
0.2
4.0 6.1 9.3 45.3
FlLT / IE /GAC
FlLT/PTA/GAC
FlLT / PTA lIE
CCIIE/PTA CC/IE/GAC
CC/PTA/GAC FlLT / CC / IE / PTA
FlLT / CC lIE / GAC FlLT / CC / PTA / GAC
Other Combinationsi
3 4
4
4
8.0 13.0 15.2 17.2 1.3
Note: These data were calculated from Table G2 by subtracting the actual proportion of systems using a specific combination of treatment options by the estimated proportion of systems needing that combination. This result is divided by the estimated proportion.
'Estimated percentages were calculated from EPA document, Benefits and Costs of the 1986 Amendments to the SDWA (Wade Miller, 1989).
bActual percentages were obtained from FRDS multiple treatment data search results.
'The number of systems using alternative treatments includes those that do not directly affect SDWA treatment requirements, (e.g. fluoride treatment).
dFiltration includes all fIltration processes: Cartridge, greensand, DE, rapid sand, slow sand, ultrafiltration and direct filtration.
'Corrosion (CC) control includes treatment process codes I, H, L. (See Exhibit Fl.)
rlon exchange (IE) relates to code E, and includes activated both alumnina, and anion and cation exchange.
gAeration (PTA) includes all aeration processes: Cascade, diffused, packed tower, slat spray, and spray aeration.
hGAC includes both powdered and granulated activated carbon processes.
;This category includes treatment combinations that are not considered feasible and combinations estimated to affect less than one percent of all systems.
jAn' • ' occurs wherever the estimated value was zero, in which case there would have been a division by zero.
-
32
The situation is quite different for disinfection. Here, many more systems employ
methods for disinfection as their only method of treatment than is estimated to be acceptable
under widespread compliance with the 1986 amendments. Furthermore, three of the dual
treatment strategies involving disinfection are "over subscribed" as well. This means that many
of these systems are likely to install additional treatment technologies as they are faced with
decisions regarding full compliance with the regulations. And, according to the predictions of
need, these strategies will involve at least three distinct treatment processes. Since these are
being used by only a few, if any, systems currently, this is obviously a top priority for
technology developmer~t, testing, and evaluation.
One of the most encouraging aspects of this analysis is that the short falls relative to
most treatment combinations decrease as one moves to categories for larger systems. This
pattern is most evident for the treatment combinations involving two technologies.
Accordingly, many of these treatment combinations are being used by small and medium sized
systems, but not by the very small ones. These very small systems will undoubtedly be among
the last to install elaborate treatment technologies, both because they are more likely to receive
exemptions from treatment and because costs may be prohibitive. This is strong evidence that
these treatment combinations can be used by systems at the smaller end of the size range. It
should be possible to obtain first-hand information about these operations as part of a strategy
for adapting them for use by the very small systems.
One can find similar patterns relative to surface water systems in table 10, but there is
less that needs to be described in detail. There are fewer multiple treatment combinations
applicable to surface water quality problems, and there are also fewer very small and small
systems that rely on surface water.
POLICY IMPLICATIONS AND CONCLUSIONS
As stated above, the purpose of this report is to provide a descriptive summary of these
various operating and design characteristics of CWS's across the country. The manuscript is
one of the first in a series designed to provide a comprehensive look at the implications of the
1986 amendments. The objectives are modest relative to the scope of the overall research
effort, but they are a necessary first step. Emphasis is focused on the policy implications that
can be drawn from a careful analysis of the data. These data are also organized to help
provide a typology of representative public water systems that can be examined to better
understand the regional effects of policy implementation.
)
!
/..I
33
Emphasis has also been on the current water treatment objectives being pursued by
CWS's and the treatment processes that are already in place. This latter information is used
in conjunction with prior estimates of the probability that systems will need certain
combinations of treatment processes to set priorities for further research. It is for those smaller
systems that may require the addition of multiple water treatment processes that the financial
implications are likely to be the most severe. Finding economically feasible treatment
strategies for these systems is most challenging as well.
Much of the descriptive information about the characteristics of the CWS' s across the
country serves to reinforce what we may have suspected already. About 80% of the population
is served by only 6% of the Nation's community water systems, but these are the largest
systems. While the implementation of the 1986 amendments to the SOWA may pose some
problems for these systems, the fact remains that a large percentage of the population is served
by systems having the technical and financial resources to accommodate additional monitoring
and treatment requirements.
The fact that only 20% of the population are served by community water systems
serving fewer than 10,000 people tends to disguise the magnitude of the problems facing
systems of this size. However, the problems can be put into proper perspective by recognizing
that over 90% of the Nation's community water systems are involved in meeting the drinking
water needs of this 20% of the population. Most would agree that even the logistics of dealing
with well over 50,000 community water systems is problematic. Furthermore, since most of
these community water systems are scattered across the rural landscape throughout the country,
the problems are exacerbated by the widening gap between average incomes of rural vs. urban
residents and the declining economic base in some rural areas as well.
The proportion of small. and very small water systems exceeds the national average in
New England and in EPA's three western regions. It is here where the problems facing small
and very small systems are likely to have a disproportionately large effect. Given the wide
variations in population density and other socio-economic differences between New England,
for example, and the sparsely populated states in the West, the opportunities for restructuring
either through physical consolidation or administrative or institutional cooperation, are
dramatically different. This only serves to underscore the need to think about solutions that
accommodate the important features of our Nation's regional diversity. Without a doubt, the
inherent problems in dealing with this country's regional diversity is always one of the major challenges to implementing national policy. It is certainly true in this case, and this recognition
34
is perhaps in large measure responsible for provisions in the 1996 amendments to establish
regional centers for technical support.
We also learn from the data that systems dependent primarily on surface water tend to
be the larger ones. Thus, the vast majority of small and very small systems rely primarily on
ground water. This is perhaps the only bright spot in this whole picture because the level of
treatment necessary for these systems is often below what is needed to guarantee acceptable
levels of water quality for systems relying on surface water.
The data also suggest that issues surrounding the financing of treatment for systems
under 10,000 are compounded by the patterns of system ownership. With more than one-half
of the community water systems serving fewer than 10,000 people being privately owned, it
is difficult to understand why provisions for credit to water systems through a revolving fund
are earmarked primarily for publicly owned water systems. As written, the legislation provides
assistance from a state revolving fund only to those private systems having the greatest public
health and financial need. Clearly, without some well-established guidelines for allocating
these funds, private systems and the people they serve could well be at a competitive
disadvantage in gaining access to these funds.
There is also growing recognition that one major barrier facing small water systems is
obtaining government approval for innovative, small scale technology for monitoring and
treating drinking water. The problems seem to evolve around the amount of field-scale testing
required and the conflicting requirements among states. While this suggests the need for a
clear statement of the requirements. for testing, a clear indication of the combinations of
treatment processes needed by these small community water systems would help establish
priorities for development and testing of new technology. The recent SDWA amendments do,
however, provide treatment and monitoring flexibility, as dictated by the states, to address these
Issues.
On the basis of our analysis, there is, as would be expected, a short fall between the
number of systems serving fewer than 10,000 employing multiple treatment processes and the
estimated number required. Assuming that the data are reported accurately, there are systems
that have demonstrated success with a number of multiple treatment processes, particularly in
the small and medium-size categories. The experience gained by these systems would seem
invaluable in efforts to accelerate the process of field testing and approval of new technology.
Priorities for such analysis for ground water systems would be processes anchored by
disinfection and corrosion control, combined with either an activated carbon process or
,"
, J-
35
aeration. For surface water systems, priorities would include multiple treatment strategies
involving filtration and corrosion control, combined with ion exchange or activated carbon.
As part of EPA's efforts to develop Best Available Technologies for very small systems
and on-going research as part of this cooperative agreement, much is already known about the
costs of single treatment technologies and the differences in the economies of size across
treatment processes. However, much of this information is based on engineering estimates, and
there have been few actual installations on which to verify the cost estimates. The effects on
treatment costs as these processes are operated jointly is also not well understood, and this is
an additional priority for our ongoing research.
36
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.:
________----------------------------------------'1
37
U.S. Environmental Protection Agency. Office of Water. "Federal Reporting Data System
(FRDS-II) Data Entry Instructions", EPA 812-B-93-002, Washington, D.C., January,
1993.
U.S. Environmental Protection Agency. Office of Water. "Technical and Economic Capacity
of States and Public Water Systems to Implement Drinking Water Regulations", Report
to Congress, EPA 810-R-93-001, Washington, D.C., September, 1993.
Wade Miller Associates, Inc. "Estimates of the Total Benefits and Total Costs Associated with
Implementation of the 1985 Amendments to the Safe Drinking Water Act," prepared
for the U. S. Environmental Protection Agency, Office of Drinking Water, Arlington,
VA., 1990.
I
/
t r
APPENDIX A
Testing for Identical Distributions Using the Kolmogorov-Smirnov Test
To develop a clear perspective on the number and diversity of community water systems
(CWS) across the United States, the FRDS-II data base is used to obtain information on
various system characteristics, such as primary water source, population served, ownership,
water treatment objectives and processes in place, and two other important measures of system
size, average daily flow and design capacity. The FRDS-II Data Base as of July 1, 1994,
contains records for over 57,000 CWS's nationally. However, in any data set of this size and
complexity, the degree to which the information is accurate and up to date for individual
systems varies, and depends on the care taken by the system personnel responsible for
supplying the information to EPA. Consequently, our descriptive analysis of the data is based
on a subset of the data after observations with missing or obviously erroneous data for various
characteristics of the systems are removed.
As emphasized in the text, we eliminate observations where some of the most basic
information on population served, ownership, and treatment classification is missing. We also
eliminate systems where the information was provided, but was obviously in error because of
inconsistencies between population served, average daily production, and design capacity.
Over 45,600 community water systems (about 80% of the total) remain in the "sample". The
purpose of this appendix is to report the results of some statistical tests regarding the similarity
of the distribution of water systems by size, compared with the size distribution for the entire
57,000 systems. To the extent that they are similar, we can be confident that inferences about
the population drawn from an analysis of the sample will not be biased in any way. We are
obviously most concerned about small system categories. One might expect the quality of the
information for these systems to be more variable than for larger systems because of the lack
of personnel to do the reporting. On this basis, one might expect a larger proportion of these
systems to be eliminated from the data set initially.
The statistical test is designed to test the similarity of the two distributions of CWS's
according to the population served. This is essentially a test of the similarity in the size
distributions of the CWS' s in the two respective data sets. It would have been advisable to test
the similarity of the distributions of other system characteristics as well. This, however, was
not possible because of the missing or erroneous data in some of the observations which made
it necessary to eliminate them in the first place. More importantly, if more than one test were
conducted in sequence, the validity of each would be conditional on the results of the previous
,
}
;
-,.."
39
tests, and it would be difficult to have any confidence in the "levels of significance" of any of
these subsequent tests. The only effective way to conduct a test on more than one
characteristic would be to base it on a test of the similarity of the joint distributions. While
theoretically possible, we know of no such test that could be applied empirically in this case.
There are two commonly used statistical procedures to test the null hypothesis that two
distributions are the same. The first is a Chi-square test (Snedecor and Cochran, 1989), and
the second is the Kolmogorov-Smirnov test (Siegel, 1956). For our purposes, the Kolmogorov
Smirnov test is used rather than the Chi-squared test because it evaluates the similarity of the
distributions at all sample points. On the other hand, the Chi-squared test, evaluates the
similarity of the two distributions over intervals, and the outcome depends explicitly on how
these intervals are specified. The Chi-square test is certainly the more subjective of the two.
The testing procedure for the Kolmogorov-Smirnov test involves specifying the
cumulative frequency distribution for the theoretical distribution and comparing it with the
observed cumulative frequency distribution (Siegel, 1956). In many instances, the test is used
to compare a sample with some known continuous probability distribution, but, in the case
here, we have two empirical distributions to compare.
In particular, we compare the size distribution (as measured by population served) of
the "sample" data set with the size distribution of the original population of CWS's found in
EPA's report to Congress "Technical and Economic Capacity of States... " (EPA, 1993). The
data from the EPA report include the 57,500 CWS's in the FRDS-II data system of a year
earlier than the FRDS-II data from which our sample is drawn. It includes all systems,
regardless of the quality of the data. In testing our "sample" against this population of systems,
we are implicitly assuming that the data on retail population served is accurate. More is said
about this below. Since the distribution of systems in the EPA report distinguishes between
ground water and surface water systems, we test both distributions, as well as the distributions
for the combined systems.
The CWS's are categorized into nine size categories which are arranged in ascending
order. The data for all systems are in table AI, whereas the data for ground and surface water
systems are in tables A2 and A3, respectively.
To conduct the test and develop the test statistic, let FiX) be the specified cumulative
frequency distribution function for the size distribution of CWS's in the entire population of
water systems. That is, for any value of X (population category), the value of Frlx) is the
Table AI. Data for Kolmogorov-Smirnov Test of Size Distributions of all Community Water Systems
CWS Population Distribution 1 CWS Sample Distribution 2 Deviations in
Cumulative Population Cumulative Cumulative Proportion3
Category Frequency Proportion Proportion Frequency Proportion Proportion
< 101 17,300 0.301 0.301 13,528 0.297 0.297 0.004
101-500 18,211 0.317 0.618 14,165 0.310 0.607 0.011
501-1,000 6,207 0.108 0.726 4,917 0.108 0.715 0.011
1,001-3,300 8,318 0.145 0.871 6,897 0.151 0.866 0.005
3,301-10,000 4,085 0.071 0.942 3,414 0.075 0.941 0.001 ~ 0
10,001-50,000 2,660 0.046 0.988 2,152 0.047 0.988 0.000
50,001-75,000 260 0.004 0.992 215 0.005 0.993 0.000
75,001-100,000 121 0.002 0.994 94 0.002 0.995 0.000
> 100,000 315 0.005 1.000 249 0.006 1.000 0.000
1 CWS's distribution by system size from "Technical and Economic Capacity of States and Public Water Systems
to Implement Drinking Water Regulations" (EPA, 1993).
2 "Sample" CWS's distribution by system size constructed from FRDS-II data files for cooperative research
agreement between EPA and Cornell University (1995).
3 Cumulative deviations are in absolute value terms.
'- ..... '- ~---"""~---"''''I
Table A2. Data for Kolmogorov-Smirnov Test Size Distributions for Ground Water Systems
CWS Population Distribution 1 CWS Sample Distribution 2 Deviations in
Cumulative Population Cumulative Cumulative Proportion3
Category Frequency Proportion Proportion Frequency Proportion Proportion
< 101 16,140 0.345 0.345 12,910 0.346 0.346 0.001
101-500 15,950 0.341 0.686 12,545 0.336 0.681 0.005
501-1,000 4,980 0.107 0.793 3,967 0.106 0.787 0.005
1,001-3,300 5,814 0.124 0.917 4,804 0.129 0.916 0.001
3,301-10,000 2,374 0.051 0.968 1,912 0.051 0.967 0.001 ~ ...... 10,001-50,000 1,275 0.027 0.995 1,028 0.028 0.995 0.000
50,001-75,000 99 0.002 0.997 87 0.002 0.997 0.000
75,001-100,000 45 0.001 0.998 39 0.001 0.998 0.000
> 100,000 89 0.002 1.000 74 0.002 1.000 0.000
1 CWS's distribution by system size from "Technical and Economic Capacity of States and Public Water Systems to
Implement Drinking Water Regulations" (EPA, 1993).
2 "Sample" CWS's distribution by system size constructed from FRDS-II data files for cooperative research
agreement between EPA and Cornell University (1995).
3 Cumulative deviations are in absolute value terms.
'I I
Table A3. Data for Kolmogorov-Smirnov Test Size Distributions for Surface Water Systems
CWS Population Distribution 1 CWS Sample Distribution2 Deviations in
Cumulative Population Cumulative Cumulative Proportion3
Category Frequency Proportion Proportion Frequency Proportion Proportion
< 101 1,160 0.108 0.108 618 0.075 0.075 0.033
101-500 2,261 0.211 0.319 1,620 0.196 0.271 0.049
501-1,000 1,227 0.115 0.434 950 0.115 0.386 0.048
1,001-3,300 2,504 0.234 0.668 2,093 0.253 0.639 0.029
3,301-10,000 1,711 0.160 0.828 1,502 0.182 0.821 0.007 ~ N
10,001-50,000 1,385 0.129 0.957 1,124 0.136 0.957 0.000
50,001-75,000 161 0.015 0.972 128 0.016 0.972 0.000
75,001-100,000 76 0.001 0.979 55 0.007 0.979 0.000
> 100,000 226 0.021 1.000 175 0.021 1.000 0.000
1 CWS's distribution by system size from "Technical and Economic Capacity of States and Public Water Systems to
Implement Drinking Water Regulations" (EPA, 1993).
2 "Sample" CWS's distribution by system size constructed from FRDS-II data files for cooperative research agreement
between EPA and Cornell University (1995).
3 Cumulative deviations are in absolute value terms.
\ ., .,' - ... -"',, I
43
proportion of CWS's expected to have retail service populations equal to or less than X.
Furthermore, let Six) be the observed cumulative frequency distribution for the size
distribution of CWS's in our "sample" of n observations; SiX)=k1n, and k is the number of
observations whose retail service population is equal to or less than X. Therefore, under the
null hypothesis that the "sample" has been drawn from the specified distribution FiX), Sn(X)
should be fairly close to FiX) for every value of X. The Kolmogorov-Smirnov test
concentrates on the largest of these deviations, where the test statistic given by:
(l) D = max IS/X) -FiX) I ,
where D is the greatest absolute difference in height between the two empmc distribution
functions, S and F. If an appropriately large value of D is observed, one rejects the null
hypothesis that both distributions are the same in favor of the alternative hypothesis that they
are not. The asymptotic sampling distribution of D is given by:
(2) Pr {D :s; zN -liZ} ~ L(z) as nl' nz ~ 00
where n/ and n2
respectively; and
are the numbers of observations in the original and "sample" data sets,
(4) L(z) 1-2L(-lY-' e -z;'z' ;=1
(5) J2TI ~ -(Zj-I)'n'/8z'--L e
z j=1
for z> 0,
(6) L(z) = 0 for Z:S; 0
The sampling distribution of D under H() is known, and the significance of a given critical
value of D depends on N. The critical values are found on page 251 in Siegel (1956).
In addition to containing the cumulative frequencies for the two distributions, tables Al
through A3 contain the differences in the cumulative frequencies for all CWS' s, and for when
they are separated into the two groups by primary water source. The test statistics and results
for each set of CWS's are in table A4. As can be seen from table A4, we fail to reject Ho for
-..
44
Table A4. Kolmogorov Test Statistics and Results of Hypothesis Tests
Both Ground and
Surface Water Ground Water Surface Water
Test Statistic Systems Systems Systems
N 25,437 20,770 4,665
Critical Value I 0.01 0.01 0.02
max D 0.01 0.005 0.05 J I
Test Result Fail to Reject Ho Fail to Reject Ho Reject Ho J
I I ,
1 Critical value based on Type I error level of 0.01, It is calculated as ! r1.63/N0 5
. See Siegel (1956), page 251.
.,I
both the full sample of CWS's and the subset of ground water systems. That is, we conclude
that the cumulative distributions are equivalent. In the case of the ground water systems, the
result, seems fairly robust with a maximum absolute deviation over all population categories
of only 0.005. The results are different for the test of the size distributions for surface water
systems. Because the critical value of 0.02 is below the calculated value of D, we reject ~)
and conclude that the distributions are different.
Given that these tests turned out differently for the two types of systems, a closer
examination of the distributions is warranted here, both to validate the results and discuss the
implications for our analysis. Our primary concern in having to rely on this 80% sample in
the first place has to do with retaining a representative number of small CWS' s. It was
reasonable to expect that owners of smaller systems, such as trailer parks and housing
complexes, would find it more difficult to complete the FRDS's data requirements, and would
also be less likely to see any value in spending the time to complete the necessary forms. This
would naturally result in a proportionately higher reduction in the observations in these small
size ranges compared with the number eliminated in the larger size categories.
Somewhat surprisingly, the results indicate that the proportion of smaller systems
retained is very close to the proportions in the entire population of ground water systems. For
small surface water systems, those serving under 500 people, the effects of eliminating some observations is somewhat more serious if viewed strictly in terms of the results of the statistical
tests. However, for surface water systems serving under 500 people, the percentage of systems
in the sample fell by only 3 percentage points between the total population surface water
45
CWS's and the "sample", falling from 11% to 8%. Since there are still a significant number
of systems of this size category remaining in the "sample" the only real concern is the extent
to which these systems eliminated are sufficiently different than those retained to "bias" any
inferences drawn from the sample.
It is impossible to know the answer to this question, but given the size of the systems,
they might be expected to be quite homogenous as a group, at least in terms of the several
general descriptive characteristics of the systems being examined in this report. It is also true
that in "cleaning" the FRDS's data for our purposes, there were many systems where. the
population served was set at 25, the lowest value possible by federal PWS definition, and either
average daily flow or design capacity was set much higher than reasonably expected for that
population size. It is impossible to know whether these systems were actually large or small
ones. There is every reason to believe that this problem existed in the data in EPA's report
to Congress which is used as the base of comparison for the hypothesis tests. If this is true,
it is likely that these data slightly over estimate the proportion of small systems. On the
strength of these arguments, we are not overly concerned about the possibility of systematic
bias in the analysis of small systems as a result of our necessary "sampling" procedure.
A more serious concern would certainly be in the effects of our "sampling" on medium
and large systems because of the potential diversity of these CWS's. However, if the small
system categories are removed from the test procedure, all tests fail to reject Ho' Thus, there
seems to be little concern over systematic bias in the analysis of these larger systems.
Some comments regarding the Kolmogorov-Smirnov test procedure also support our
contention that the analysis based on our sample lead to reasonable results. Since the critical
values of the Kolmogorov-Smirnov test depend on N, the large number of observations in the
data sets being examined here reduce critical values substantially over what they would be in
most tests which involve much smaller samples. Under these conditions, failure to reject the
null hypothesis is difficult using the Kolmogorov-Smirnov test, and the similarity in
magnitudes of the test statistic and the critical value for the tests of surface water systems is
encouraging. The results of the tests could also have been influenced by disaggregating the
categories further for a given N. We chose not to do this because we thought it important to
keep the categories consistent with EPA's delineation used for policy purposes.
In conclusion, the testing procedure provides optimistic results concerning the validity -and representative nature of the "sample" constructed for the descriptive analysis in this report.
Test procedures failed to reject Ho for the entire "sample" of CWS's and for the subset of
r r / i
46 .,A rground water systems. But, the test led to a rejection Ho in favor of the alternative hypothesis I.
for the subset of surface water systems, in large measure due to the number of small systems
that had to be eliminated from the analysis. However, because it is expected that this group
may be quite homogenous in terms of system characteristics and operation procedures, it is
unlikely that our strategy would lead to any systematic bias in the results. Therefore, further
analyses based on the 80% "sample" described here should, to the best of our knowledge,
provide representative results for all CWS's across the country and lead to applicable and
reliable implications regarding the characteristics of water systems across the country and v
compliance with the 1986 amendments to EPA's Safe Drinking Water Act.
I-i
I
APPENDIX B
Characteristics of Community Water Systems by EPA Region
The purpose of this appendix is to provide a self-contained description of the regional
diversity of community water systems throughout the United States. The data reported here
are used in the text to support or highlight the regional significance of various provisions of
the 1986 amendments to the Safe Drinking Water Act and changes brought about by the recent
1996 amendments to the SDWA.
As in any regional analysis, it is important to define regions that highlight the diversity
that is important for the policy analysis at hand. Almost without exception, the practice of
delineating regions on the basis of state, or even local political boundaries is in many respects
inappropriate for the task. However, there is also rarely any choice because its on the basis
of these boundaries that most data are available. In this case, we do have data at the state
level, and some consideration was given to defining our own regions based primarily on
geographic proximity, climate, and to some extent on urban orientation. This strategy was
abandoned, primarily because the benefits in terms of being able to group similar areas seemed
small relative to those associated with doing the analysis based on the EPA's 10 administrative
regions. Given that we would still have been limited to regions defined on the basis of state
boundaries, there seemed to be little point in merely moving four or five states from one region
to another.
For administrative purposes, the Environmental Protection Agency has established 10
regional offices, each serving several of the surrounding states and territories of the United
States, such as American Samoa and/or freely associated states, such as the Marshall Islands.
For the purpose of this report and future research, we include in these regions only the 50
United States and the District of Columbia (DC). As stated in the earlier text, this excludes
about 700 systems. The 10 regions are named for the locations of their regional offices; the
states associated with each region are shown in exhibit B1.
A Regional Overview
Through tables Bland B2, one can begin to understand the regional distribution of the -community water systems and the proportion of the populations served by them. The
distribution of systems by size across regions in general is consistent with that for the Nation.
One could hardly expect any difference given that 87% of the systems nationwide are either
I
I
48 r·
Exhibit B1. EPA Regions, Regional Office Location, and States included.
EPA Region Regional Office States in Region )
1
2
3
4
5
6
7
8
9
10
Boston
New York
Philadelphia
Atlanta
Chicago
Dallas
Kansas City
Denver
San Francisco
Seattle
ICT, ME, NH, RI, VT
NJ, NY
DC,DE,MD,PA,VA, WV IAL,FL,GA,KY,MS,NC, SC,TN I
IL, IN, MI, MN, OH, WI J
AR, LA, NM, OK, TX t,lA, KS, MO, NE ~
I ICO, MT, NO, SD, UT, WY
AZ, CA, HI, NV
AK, ID, OR, WA
small or very small. However, in three regions (Atlanta, Chicago, and San Francisco), the
proportions of small and very small systems are lower than the national average; in the San
Francisco Region the proportion is significantly lower. The proportions of the populations
served by these small systems in the regions are lower as well.
In contrast, the proportion of small and very small systems exceeds the national average
significantly in New England and in the three EPA regions served by Dallas, Denver, and
Seattle. The proportion of the population served by these systems in the Dallas region is more
than double the national average.
Average Daily Production and Design Capacity
From table 3 in the text, it is clear that while there is some consistency in water
production, as measured by average daily flow, and design capacity on a per capita basis across , system size categories, the variation both within and between groups is substantial. The same
j r
is true at the regional level (table B3). In six of the EPA regions, average daily water .. production per capita is below the national average. As would be predicted by the regression
equations in appendix C, the four regions where per capita production is the lowest are in the
Midwest and the East: the Chicago, Boston, New York, and Philadelphia regions. Per capita -production in both the Kansas City and Atlanta regions is just slightly below the national ".
average and is explained in large measure by large proportion of the population living in rural
areas. In the case of the Atlanta region, this rural orientation more than offsets the fact that
/
Table B 1. Percentage Distribution of Community Water Systems by System Size
Population
Category Nation
- - - -
1
Boston
- - - -
2
New York
- - - - -
EPA Region Number with Regional Headquarters
3 4 5 6 7 8
Phila. Atlanta Chicago Dallas Denver Kans. City
- - - - - - - - % - - - - - - - - - - - - -
9
San Fran.
- - - -
10
Seattle
- - - -Very Small
< 101
101 to 500
29.6
31.0
41.4
35.8
38.7
29.3
31.6
33.4
26.9
29.7
21.8
28.8
24.7
31.2
20.0
37.4
34.7
33.0
27.1
22.8 48.0
32.2
Small
510 to 1,001
1,001 to 2,500
2,501 to 3,300
10.8
12.0
3.1
5.5
6.7
1.8
8.4
7.8
2.2
9.9
10.5
3.1
10.7
12.4
4.1
14.5
15.5
3.2
12.4
15.1
4.0
14.7
15.9
2.8
10.6
10.5
2.0
9.2
10.9
3.2
5.7
6.0
1.7 +:'0
Medium
3,301 to 5,000
5,001 to 10,000
3.3
4.2
1.4
2.9
2.8
3.8
3.0
3.4
4.0
5.6
3.9
4.9
4.1
4.3
2.9
3.3
2.3
2.9
3.8
6.9
1.2
2.0
Large
10,001 to 50,000
50,001 to 75,000
75,001 to 100,000
4.7
0.5
0.2
3.2
0.5
0.3
5.8
0.5
0.0
3.9
0.3
0.2
5.5
0.5
0.2
6.2
0.6
0.2
3.5
0.3
0.1
2.4
0.2
0.1
3.2
0.3
0.2
10.7
2.1
1.1
2.9
0.1
0.1
Very Large
> 100,000 0.5 0.5 0.7 0.7 0.5 0.4 0.4 0.4 0.3 2.1 0.2
I
Table B2. Percentage of Population Served by Community Water Systems by System Size
Population
Category Nation
- - - -
1
Boston
- - - -
2
New York
- - - - -
EPA Region Number with Regional Headquarters
3 4 5 6 7 8
Phila. Atlanta Chicago Dallas Denver Kans. City
- - - - - - - - % - - - - - - - - - - - - -
9
San Fran.
- - - -
10
Seattle
- - - -Very Small
< 101
101 to 500
0.4
1.9
0.8
2.7
0.3
1.3
0.4
1.8
0.4
1.8
0.3
1.8
0.5
2.5
0.4
3.8
0.8
3.0
0.1
0.4
1.6
4.2
Small
510 to 1,001
1,001 to 2,500
2,501 to 3,300
1.9
4.6
2.2
1.3
3.8
1.7
1.1
2.2
1.1
1.7
3.9
2.0
1.9
4.9
2.8
2.5
5.7
2.1
2.8
7.7
3.6
4.0
9.5
3.0
2.9
6.1
2.1
0.6
1.5
0.7
2.4
5.7
3.0 VI 0
Medium
3,301 to 5,000
5,001 to 10,000
3.2
7.3
1.8
6.9
1.9
4.7
2.8
5.4
3.9
9.6
3.7
8.3
5.3
9.5
4.5
8.7
3.4
7.7
1.3
4.1
2.9
8.4
Large
10,001 to 50,000
50,001 to 75,000
75,001 to 100,000
24.7
6.8
4.2
26.4
8.4
8.9
22.0
5.7
0.3
19.2
4.2
2.8
27.9
6.7
3.7
30.9
8.8
4.8
22.3
5.3
4.1
19.1
4.6
1.5
23.5
7.2
7.6
21.8
10.4
7.5
37.7
2.5
4.9
Very Large
> 100,000 42.9 37.4 59.3 55.7 36.5 31.2 36.4 40.7 35.7 51.5 26.7
.,.., --.- ~--.~ •. -<'.~",-_.-.,,-.-'~- ". - •. ..__.... _-~ ~_.._-- "'-"~ I -- -- -<o.~'- '. -- ,", _. - ..' - - ' .._.- -
Table B3. Average Water Production" and Design Capacity of Community Water Systems
EPA Region Number with Regional Headquarters
Water 1 2 3 4 5 6 7 8 9 10 Source Nation Boston New York Phila. Atlanta Chicago Dallas Denver Kans. City San Fran. Seattle
- - - - - - - - - - - - - - - - - - - - - % - - - - - - - - - - - - - - - - - - - -
Daily Production (1,000 gal.) 714 444 1,005 562 610 621 565 381 428 3,147 325 Design Capacity (1,000 gal.) 1,875 1,107 1,916 1,304 1,267 1,342 1,745 1,250 1,110 10,143 1,075
Retail Population 4,214 3,088 5,945 4,483 4,204 4,309 3,183 2,637 2,772 12,468 1,722 VI
Hookups 1,246 803 1,362 1,262 1,420 1,339 1,018 946 803 3,123 560
Retail Population/Hookup 5 5 7 7 4 5 4 4 4 5 7
Daily Production/Capita 126 114 114 105 120 102 142 124 135 166 154
Daily Production/Hookup 510 483 564 596 441 424 465 386 492 718 729
Design Capacity/Capita 789 722 641 530 659 545 901 868 982 1,192 1,233
Design Capacity/Hookup 2,832 2,791 2,481 2,583 2,256 2,050 2,919 2,619 3,416 4,359 4,609
"Water production is equivalent to average daily flow.
/~- --
.. I
L
I
52
water systems in the South tend to have higher water production rates. A similar pattern is
evident in design capacity per capita, with the exception of the Kansas City region where
design capacity per capita is above the national average.
System Ownership
As is highlighted in the text, ownership of the nation's community water systems is
primarily in the hands of the private sector which controls 53% of the systems) and the many
local governments across which own a 41 % share. The remaining systems are either owned
jointly by public and private interests, the Federal and state governments, or Native Americans.
All regions, likewise are dominated by the private and local government, and, for the most part
are consistent with the pattern at the national level (table B4). However, in the Midwest
regions, those whose regional offices are in Chicago and in Kansas City, local government
ownership is substantially higher than the national average, 60 and 73%, respectively. In the
Dallas and Seattle regions there are substantially higher proportions of systems owned jointly
by public and private interests, 11 and 18%, respectively.
Water Treatment
As is seen in table B5, the distribution of systems in the three broad treatment
classifications, "treated", "mixed", and "untreated", differs substantially by EPA region.
Nationally, 60% of CWS's apply treatment to at least one of their water sources; while one
third do no treatment at all. For water systems in the Boston region, these percentages are
nearly reversed, with two-thirds of the systems indicating that their water is "untreated". This
region's higher proportions of ground water systems and systems of smaller size may explain
most of this difference. At the other end of the spectrum, it is in the New York and Atlanta
regions where the lowest proportions of untreated systems are found, 11 and 19% respectively.
Distribution of cws 's by Primary Water Source
Both the distributions of the number of CWS's by primary water source and the
percentage of the water supplied differ substantially by EPA region (tables B6 and B7). The
percentage of ground water systems ranges from a low of 72% in the New York region to a
high of 89% in the Seattle region. This variation is to be expected, and it has implications for
the cost of compliance with EPA regulations, assuming that the level of treatment required for
ground water will, in general, always be less than for surface water.
t
}
-
Table B4. Percentage Distribution of Community Water Systems by Ownership
EPA Region Number with Regional Headquarters
Ownership 1 2 3 4 5 6 7 8 9 10 Category Nation Boston New York Phila. Atlanta Chicago Dallas Denver Kans. City San Fran. Seattle
- - - - - - - - - - - - - - - - - - - - - % - - - - - - - - - - - - - - - - - - - - -
Federal Government 1.0 0.1 0.4 0.9 0.7 0.3 0.7 0.3 0.7 6.0 1.5
Private 52.6 76.1 55.1 62.7 62.0 38.1 56.8 26.1 48.8 53.2 48.5
State Government 1.0 0.5 1.0 0.8 0.9 1.3 0.8 0.4 0.5 4.7 0.7
Local Government 41.2 23.3 41.8 35.5 35.9 59.5 30.2 73.1 50.0 32.9 29.7
Mixed public/private 3.9 0.1 1.6 0.0 0.3 0.1 11.4 0.1 0.0 3.1 18.2
Native American 0.3 0.0 0.2 0.0 0.1 0.7 0.0 0.0 0.0 0.0 1.4
Vl w
Table B5. Percentage Distribution of Community Water Systems by Treatment Classification
EPA Region Number with Regional Headquarters
Treatment 1 2 3 4 5 6 7 8 9 10
Classification Nation Boston New York Phila. Atlanta Chicago Dallas Denver Kans. City San Fran. Seattle
- - - - - - - - - - - - - - - - - - " - - % - - - - - - - - - - - - - - - - - - - - -Treated 60.8 24.4 78.3 56.4 76.4 46.0 71.4 52.7 51.9 25.1 63.0
Untreated 32.0 65.6 10.8 35.9 19.5 46.9 27.3 41.4 39.6 38.2 34.9
Mixed 7.2 9.9 10.8 7.7 4.2 7.1 1.3 5.9 8.5 36.7 2.1
Note: Treated Systems imply that the water from all ofa system's sources is subjected to treatment. Untreated systems apply no treatment for any of its
water sources. For the system in the mixed treatment classification, water from some sources is treated, while water from others is not.
I
Table B6. Percentage Distribution of the Number of Community Water Systems by Water Source
Water
Source Nation Boston
2
New York
3
Phila.
EPA Region Number with Regional Headquarters
4 5 6 7 8 Atlanta Chicago Dallas Denver Kans. City
0/0
9 San Fran.
_
10
Seattle
Ground, nonpurchased
Ground, purchased
78.7
3.2
85.9
0.4 71.3
1.0
77.0 1.4
79.7
3.8
81.6
2.6
74.9
4.0
78.1
6.1
75.8
4.5
83.2
0.6
85.4
3.9
Surface, nonpurchased
Surface, purchased
8.2
9.7
9.7
3.9
8.5
19.2
13.1
8.4
7.2
8.9
4.3
11.4
7.7
13.5
6.1
9.7
10.9
8.6
13.0
2.9
8.4
2.1 VI ~
Ground UDI, nonpurchased"
Ground UDI, purchased"
0.1
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.4
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.2
0.0
0.2
0.2
0.1
0.0
Totals
Ground Water Systems 81.9 86.3 72.3 78.4 83.5 84.3 78.8 84.2 80.3 83.7 89.3
Surface Water Systems' 18.1 13.7 27.7 21.6 16.5 15.7 21.2 15.8 19.7 16.3 10.7
"UDI means that the ground water is under the direct influence of surface water. Thus, they are subject to the same regulations as surface water and are
included in the surface water system's total.
. " - ...... ~-_ .. _-_. ". ...... --- .......... "'--- -"" ~I,
Table B7. Percentage Distribution of the Water Production by Community Water Systems by Water Source
Water Source Nation
1 Boston
2
New York 3
Phila.
EPA Region Number with Regional Headquarters 4 567
Atlanta Chicago Dallas Denver --- _ % - --- ---
8 Kans. City ---
9 San Fran.
10 Seattle
Ground, nonpurchased
Ground, purchased
32.4
0.9
11.2
0.1
20.3
0.2
12.7
0.5
44.3
1.5
23.8
0.6
31.7
0.8
39.6
1.4
18.8
0.3
41.4
0.1
39.5
6.8
Surface, nonpurchased
Surface, purchased
58.4
8.2
80.6
8.0
71.4
8.2
74.4
12.4
47.2
6.8
55.2
20.5
54.6
12.9
55.0
4.1
70.1
10.7
56.9
1.4
50.1
3.6 VI VI
Ground UDI, nonpurchased' 0.1 0.0 0.0 0.1 0.3 0.0 0.0 0.0 0.0 0.1 0.1
Ground UDI, purchased' 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Totals
Ground Water Systems 33.3 11.3 20.4 13.2 45.7 24.4 32.4 41.0 19.2 41.5 46.2
Surface Water Systems' 66.7 88.7 79.6 86.8 54.3 75.6 67.6 59.0 80.8 58.5 53.8
'UDI means that the ground water is under the direct influence of surface water. Thus, they are subject to the same regulations as surface water and are included in the surface water system's total.
I
56 JI -rPerhaps a more surprising result is that in the West, (regions 7,8, and 9), over 40% of i.
the total water production is from ground water sources. This is substantially above the 33%
figure nationally, and it is nearly four times the percentage of water from ground water sources
in New England and the Philadelphia region.
j
-
APPENDIX C
Relationship Between Population Served and System Flow and Design Capacity
Everyone would agree that there is a high correlation between the population served by
a community water system and its average daily flow and design capacity. In an attempt to
establish these relationships in a formal way, we use a sample of over 11,000 systems in the
FRDS-II Data Base to estimate two separate equations, one for average daily flow and one for
design capacity. Summary data on the variables used in the estimation appear in table Cl.
Even though the focus of this study is on small water systems, the 11,000 observations used
to estimate the equations include observations from all systems in FRDS-II for which measures
of output and design capacity are reported, be they large or small. Having this added
variability in the data helped to estimate the coefficients in the model with greater precision,
and helped improve the ability of the model to provide more accurate predictions of both
average design capacity and average daily flow.
Table Cl. Variables for Regressions on Average Daily Flow and Design Capacity
Standard
Variable Name Mean Deviation Minimum Maximum
Average Daily Flow (gal./day) 999,103 9,861,350 500 780,000,000
Design Capacity (gal./day) 2,551,726 21,519,384 1,000 1,440,000,000
Retail Population 6,194 46,333 8 3,000,000
Number of Hookups 1,902 11,513 1 500,000
Dummy Variables: a
WSSURF: Surface water=1 0.181 0,385 0 1
WSPURCH: Purchase water=1 0.074 0.262 0 1 OWNF: Federal government owned=1 0.007 0.493 0 1 OWNS: State government owned=1 0.008 0.090 0 1
OWNL: Local government owned=1 0.481 0.500 0 1
SRVRES: Residential service area=1 0.974 0.159 0 1
SRVSRES: Semi-residential service area=1 0.017 0.128 0 1
URBAN: Located in MSA=1 0.507 0.500 0 1
EPASOUTH: EPA Region 4,6, or 9=1 0.512 0.500 0 1 EPAWEST: EPA Region 5,6,7,8,9, or 10=1 0.471 0.500 0 1 .
a The means of the dummy variables are the proportions of observations with a value of 1.
i
1
58
For this reason, it is not surprising that the average retail population in the sample is
,,
,fj
,"about 6,200, while the number of retail hookups averaged about 1,900. Average design
capacity was about 2.6 million gallons per day, supporting an average flow of just under a
million gallons per day. The primary water source for about 18% of the water systems in the
data set is surface water, and only 7% purchase any water from other systems. Nearly half are )rI
Jowned by local governments, whereas about 97% serve residential areas. About half are in
Metropolitan Statistical Areas (MSA), and about half are in EPA regions in the South or the
West, but these regional delineations are not mutually exclusive.
The first equation that is estimated is the one for average daily flow, in gallons per day.
This measure of output is regressed against the size of the retail population and the number of
commercial hookups, as well as a number of dummy variables to control for differences in the
primary water source, whether or not the system purchases water from another system, whether
or not the system serves residential or semi-residential areas, and whether or not the system
is located in a Metropolitan Statistical Area. Dummy variables also account for any differences
due to whether or not the system is private, or publicly owned. Finally, differences in average
daily flow due to regional location are accounted for by dummy variables for the South and
the West.
The second equation that is estimated is for design capacity, again measured in gallons
per day. This is regressed on the same variables as in the equation for average daily flow,
except that average daily flow is also included as a regressor. The hypothesis here is that
expectations about the required average daily flow affect decisions about design capacity, but
not vice versa.9
For estimation purposes, the continuous variables are transformed into their logarithmic
form, and the results of the estimation are in table C2. In general, the estimated equations
I
perform quite well, with an R2 of 0.80 and 0.92 for the equations for design capacity and /'
average daily flow, respectively. The signs on the coefficients of the variables are also as
expected, and the t-ratios are high as well.
9 Because average daily flow itself is estimated and it also appears as a regressor in the equation -for design capacity, it was necessary to purge the variable for average daily flow of any unexplained random component before using it as an explanatory variable in the second regression. This was accomplished by using the predicted values from the average daily flow equation as the regressor in the design flow equation. This is equivalent to an instrumental variable procedure (Judge et al., 1988).
59
Table C2. Regression Equations for Average Daily Flow and Design Capacity
"Average Daily Flow Design Capacity
Variable Coefficient Std Error t-ratio Coefficient Std Error t-ratio
2 2R =0.92 R =0.80
INTERCEPT 5.20 0.08 63.26 7.55 0.10 77.65
PPRODSQ a 0.01 0.00 12.18
LOGPOP a 0.69 0.02 41.91 0.29 0.03 9.59
LOGHOOK a 0.10 0.02 6.07 0.23 0.02 11.41
WSSURF 0.20 0.02 11.03 -0.11 0.03 -3.92
WSPURCH -0.23 0.02 -9.25 -0.22 0.04 -6.01
OWNF 0.54 0.07 7.95 0.41 0.10 4.19
OWNS 0.48 0.07 7.19 0.56 0.10 5.85
OWNL 0.25 0.01 16.92 0.13 0.02 6.53
SRVRES -0.12 0.06 -2.07 -0.20 0.09 -2.39
SRVSRES 0.21 0.08 2.74 -0.27 0.11 -2.54
URBAN 0.03 0.01 2.46 0.12 0.02 7.26
EPASOUTH 0.07 0.01 5.93 0.06 0.02 3.70 EPAWEST 0.17 0.01 14.70 0.40 0.02 23.44
LPOPHOOK a 0.02 0.00 13.68
a The variables used in the regressions are all defined in Table!, except for:
PPRODSQ = [log(average daily flow)]2 LOGPOP = log(retail population) LOGHOOK = log(number of hookups) LPOPHOOK = log(retail population) x 10g(number of hookups).
Because the continuous variables in the equations are specified in logarithmic form, the
coefficients on these variables can be interpreted as elasticities -- that is, they reflect the
percentage change in the dependent variable as the independent variable changes by one
percent. For example, as the retail population increases by one percent, design capacity
increases by 0.29 percent. Similarly, for a one percent increase in the number of hookups,
design capacity increases by 0.23 percent. The situation is not quite that simple for the effect
of average daily flow on design capacity, because it is the square of the logarithm of average
daily flow that appears in this equation. Thus, the elasticity of design capacity with respect -to average daily production is not constant. It is twice the value of the coefficient times the
logarithm of the variable, 0.02 * In (average daily flow), in this case. By examining the
coefficients on the dummy variables, it is not surprising that the design capacity is higher for
.
i
.' )
60 J
J-systems in the South and the West and for those in urban areas. Compared with systems that ! serve non-residential areas, systems that serve residential and semi-residential areas have
"
smaller design capacities. The design capacities of private systems are generally smaller than·
systems owned by the government, and are smaller for systems that purchase water and rely
primarily on surface rather than ground water.
In terms of the effects of the dummy variables, the story is about the same for the
equation to predict average daily flow as it is for design capacity. The two exceptions are:
the average daily flow is higher for surface water systems than for ground water systems, and
average daily flow is also higher if the system serves a semi-residential area. Similarly, as
both retail population and the number of hookups increase, the average daily flow rises as well.
Because of the cross product term (the product of the logarithm of population and the
logarithm of hookups), the elasticities of the average daily flow are again not constant. For
each variable, they depend on the level of the other variable in the cross product term. That
is, the elasticity of average daily flow with respect to retail population is 0.69 + 0.02 * In
(number of hookups). For the number of hookups, the elasticity of average daily production
is 0.10 + 0.02 * In (retail population). 10
10 These elasticities are essentially the logarithmic derivatives of a function of the general form In y = In a + b In x + c (In x/ + d [(In x) (In z)} + e (In z/ + fin z. For this function we have a In y / a In x = b + 2 c (In x) + d (In z)}, and a In y /a In z = f + 2 e (In z) + d (In x). In the estimated functions above, not all the terms in this general expression are present.
APPENDIX D
Summary Tables for General Water Treatment Objectives
of Community Water Systems
Table D1. General Treatment Objectives of Very Small Community Water Systems'
Single Treatment Multiple Treatments Treatment Objective Obj. Code Systems Percentage Systems Percentage
Surface Water SystemsC
Additional Treatment Elsewhere A 0 0.0 0 0.0 Disinfection By-Product Control B 0 0.0 14 0.9 Corrosion Control C I 0.1 91 5.7 Disinfection D 218 13.7 688 43.2 Dechlorination E 0 0.0 3 0.2
Iron Removal F 4 0.3 44 2.8 Inorganics Removal I 0 0.0 24 1.5 Manganese Removal M 0 0.0 8 0.5
No Treatment b N 777 48.8 1,159 72.8 Organics Removal 0 0 0.0 44 2.8
Particulate Removal P 57 3.6 512 32.2 Radionuclides Removal R 0 0.0 15 0.9 Softening S I 0.1 62 3.9 Taste/Odor Control T I 0.1 59 3.7 Other (Process Fluoridation) Z 1 0.1 41 2.6
Ground Water Systemsd
Additional Treatment Elsewhere A 0 0.0 0 0.0 Disinfection By-Product Control B 4 0.0 27 0.1 Corrosion Control C 40 0.2 748 3.6 Disinfection D 7,196 34.7 9,777 47.2 Dechlorination E I 0.0 12 0.1
Iron Removal F 84 0.4 1,057 5.1
Inorganics Removal I 13 0.1 120 0.6 Manganese Removal M 6 0.0 388 1.9
No Treatment b N 9,984 48.2 15,553 75.1 Organics Removal 0 6 0.0 130 0.6
Particulate Removal P 75 0.4 361 1.7 Radionuclides Removal R 7 0.0 45 0.2 Softening S 100 0.5 549 2.7 Taste/Odor Control T 29 0.1 447 2.2 Other (Process Fluoridation) Z 32 0.2 514 2.5
, Frequencies exclude those system which apply no trealmentthemselves. but purchase treated water, since unable to tie specific treatment objective to water utilized; i.e. systems with trealment objective~N (no trealment) and trealment process ~ 996
(treatment applied by seller). -h For sole trealments. no trealment implies no trealment at all source or plant locations. For the general multiple classification, no
treatment implies that the system applies no treatment to at least one source or plant location and may be in addition to other treatments.
, total systems ~ 1,59t
d total systems = 20,708
62
Table D2. General Treatment Objectives of Small Community Water Systems'
Single Treatment Multiple Treatments
Treatment Objective Obj. Code Systems Percentage Systems Percentage
Surface Water SystemsC
Additional Treatment Elsewhere A a 0.0 2 0.1 Disinfection By-Product Control B a 0.0 61 3.0 Corrosion Control C 4 0.2 400 19.9 Disinfection D 356 17.7 1,364 67.9 Dechlorination E a 0.0 a 0.0
Iron Removal F a 0.0 148 7.4 Inorganics Removal I a 0.0 62 3.1 Manganese Removal M a 0.0 32 1.6
No Treatment b N 443 22.0 1,248 62.1 Organics Removal 0 a 0.0 98 4.9
Particulate Removal P 35 1.7 1,008 50.1 Radionuclides Removal R a 0.0 18 0.9 Softening S 5 0.2 236 11.7 Taste/Odor Control T a 0.0 231 11.5 Other (Process Fluoridation) Z 1 0.0 1,068 53.1
Ground Water Systemsd
Additional Treatment Elsewhere A a 0.0 a 0.0 Disinfection By-Product Control B a 0.0 10 0.1 Corrosion Control C 18 0.3 760 10.7 Disinfection D 2,630 36.9 4,956 69.6 Dechlorination E a 0.0 1 0.0
Iron Removal F 22 0.3 1,043 14.6 Inorganics Removal I a 0.0 58 0.8 Manganese Removal M 1 0.0 196 2.8
No Treatment b N 1,499 21.0 3,818 53.6 Organics Removal 0 a 0.0 161 2.3
Particulate Removal P 3 0.0 259 3.6 Radionuclides Removal R a 0.0 12 0.2 Softening S 22 0.3 376 5.3 Taste/Odor Control T 5 0.1 389 5.5 Other (Process Fluoridation) Z 38 0.5 1,017 14.3
• Frequencies exclude those system which apply no treatment themselves, but purchase treated water, since unable to tie specific treatment objective to water utilized; i.e. systems with treatment objective=N (no treatment) and treatment process = 996
(treatment applied by seller).
b For sole treatments, no treatment implies no treatment at all source or plant locations. For the general multiple classification, no treatment implies that the system applies no treatment to at least one source or plant location and may be in addition to other -treatments.
C total systems = 2,010
d total systems = 7,124
63
Table D3. General Treatment Objectives of Medium Community Water Systems'
Single Treatment Multiple Treatments Treatment Objective Obj. Code Systems Percentage Systems Percentage
Surface Water SystemsC
Additional Treatment Elsewhere A 0 0.0 1 0.1 Disinfection By-Product Control B 0 0.0 55 4.8 Corrosion Control C 1 0.1 392 33.9 Disinfection D 155 13.4 882 76.4 Dechlorination E 0 0.0 2 0.2
Iron Removal F 0 0.0 128 11.1 Inorganics Removal I 0 0.0 67 5.8 Manganese Removal M 0 0.0 42 3.6
No Treatment b N 151 13.1 592 51.3 Organics Removal 0 0 0.0 104 9.0
Particulate Removal P 27 2.3 728 63.0 Radionuclides Removal R 0 0.0 16 1.4 Softening S I 0.1 133 11.5 Taste/Odor Control T 0 0.0 244 21.1 Other (Process Fluoridation) Z 1 0.1 318 27.5
Ground Water Systemsd
Additional Treatment Elsewhere A 0 0.0 0 0.0 Disinfection By-Product Control B 0 0.0 7 0.4 Corrosion Control C 5 0.3 248 14.6 Disinfection D 516 30.4 1,274 74.9 Dechlorination E 0 0.0 0 0.0
Iron Removal F 3 0.2 308 18.1 Inorganics Removal I 0 0.0 19 1.1 Manganese Removal M 0 0.0 56 3.3
No Treatment b N 230 13.5 889 52.3 Organics Removal 0 0 0.0 57 3.4
Particulate Removal P 1 0.1 124 7.3 Radionuclides Removal R 0 0.0 5 0.3 Softening S 2 0.1 125 7.4 Taste/Odor Control T 5 0.3 145 8.5 Other (Process Fluoridation) Z 12 0.7 383 22.5
a Frequencies exclude those system which apply no treatment themselves, but purchase treated water, since unable to tie specific treatment objective to water utilized; i.e. systems with treatment objective=N (no treatment) and treatment process = 996 (treatment applied by seller).
b For sole treatments, no treatment implies no treatment at all source or plant locations. For the general multiple classification, no -treatment implies that the system applies no treatment to at least one source or plant location and may be in addition to other treatments. , .
total systems = 1,155
d total systems = 1,700
C
64
Table D4. General Treatment Objectives of Large Community Water Systems'
Single Treatment Multiple Treatments Treatment Objective Obj. Code Systems Percentage Systems Percentage
Surface Water SystemsC
Additional Treatment Elsewhere A 0 0.0 4 0.3 Disinfection By-Product Control B I 0.1 121 10.4 Corrosion Control C I 0.1 465 40.1 Disinfection D 142 12.2 896 77.2 Dechlorination E 0 0.0 4 0.3
Iron Removal F 0 0.0 174 15.0 Inorganics Removal I 0 0.0 59 5.1 Manganese Removal M 0 0.0 63 5.4
No Treatment b N 139 12.0 619 53.3 Organics Removal 0 I 0.1 liD 9.5
Particulate Removal P 28 2.4 749 64.5 Radionuclides Removal R 0 0.0 9 0.8 Softening S 0 0.0 141 12.1 Taste/Odor Control T 0 0.0 312 26.9 Other (Process Fluoridation) Z 2 0.2 378 32.6
Ground Water Systemsd
Additional Treatment Elsewhere A 0 0.0 0 0.0 Disinfection By-Product Control B 0 0.0 6 0.6
Corrosion Control C 2 0.2 221 21.6
Disinfection D 193 18.8 723 70.6 Dechlorination E 0 0.0 I 0.1
Iron Removal F 0 0.0 185 18.1 Inorganics Removal I 0 0.0 24 2.3 Manganese Removal M 0 0.0 27 2.6
No Treatment b N 76 7.4 689 67.3 Organics Removal 0 1 0.1 70 6.8
Particulate Removal P 0 0.0 128 12.5
Radionuclides Removal R 0 0.0 3 0.3 Softening S 0 0.0 122 11.9 Taste/Odor Control T 1 0.1 153 14.9 Other (Process Fluoridation) Z 3 0.3 281 27.4
a Frequencies exclude those system which apply no treatment themselves, but purchase treated water, since unable to tie specific treatment objective to water utilized; i.e. systems with treatment objective=N (no treatment) and treatment process = 996 (treatment applied by seller).
b For sole treatments, no treatment implies no treatment at all source or plant locations. For the general multiple classification, no treatment implies that the system applies no treatment to at least one source or plant location and may be in addition to other treatments.
total systems = 1,161
d total systems = 1,024
C
65
Table D5. General Treatment Objectives of Very Large Community Water Systemsa
Single Treatment Multiple Treatments Treatment Objective Obj. Code Systems Percentage Systems Percentage
Surface Water Systemsc
Additional Treatment Elsewhere A 0 0.0 0 0.0 Disinfection By-Product Control B 0 0.0 21 12.7 Corrosion Control C 0 0.0 84 50.6 Disinfection D 5 3.0 140 84.3 Dechlorination E 0 0.0 2 1.2
Iron Removal F 0 0.0 25 15.1 Inorganics Removal I 0 0.0 12 7.2 Manganese Removal M 0 0.0 7 4.2
No Treatment b N 6 3.6 100 60.2 Organics Removal 0 0 0.0 28 16.9
Particulate Removal P 6 3.6 140 84.3 Radionuclides Removal R 0 0.0 "2 1.2 Softening S 0 0.0 25 15.1 Taste/Odor Control T 0 0.0 70 42.2 Other (Process Fluoridation) Z 0 0.0 80 48.2
Ground Water Systemsd
Additional Treatment Elsewhere A 0 0.0 0 0.0 Disinfection By-Product Control B 0 0.0 0 0.0 Corrosion Control C 0 0.0 19 27.9 Disinfection D 8 11.8 39 57.4 Dechlorination E 0 0.0 0 0.0
Iron Removal F 0 0.0 7 10.3
Inorganics Removal I 0 0.0 0 0.0 Manganese Removal M 0 0.0 0 0.0
No Treatment b N 1 1.5 58 85.3 Organics Removal 0 0 0.0 5 7.4
Particulate Removal P 0 0.0 15 22.1 Radionuclides Removal R 0 0.0 0 0.0 Softening S 0 0.0 11 16.2
Taste/Odor Control T 0 0.0 12 17.6 Other (Process Fluoridation) Z 0 0.0 17 25.0
• Frequencies exclude those system which apply no treatment themselves, but purchase treated water, since unable to tie specific treatment objective to water utilized; i.e. systems with treatment objective=N (no treatment) and treatment process = 996 (treatment applied by seller). -
b For sole treatments, no treatment implies no treatment at all source or plant locations. For the general multiple classification, no treatment implies that the system applies no treatment to at least one source or plant location and may be in addition to other " treatments.
C total systems = 166
d total systems = 68
I J ,J
APPENDIX E
Summary Tables for CWS's Multiple Water Treatment Objectives
Table EI. Multiple Treatment Objectives Found in Medium Community Water Systems Treatment Ground Water Systems Surface Water Systems
Objectives" Number Percent Number Percent
BCDFIMOP 9 0.92 BCDFPT 6 0.61
C 5 0.38 CD 80 6.11 30 3.06 CDF 39 2.98
CDFIMOPT CDFM CDFMOP CDFO CDFP
9 5 6 6
0.69 0.38 0.46 0.46
6
8
0.61
0.81
CDFPST 8 0.81 CDFPT 16 1.63 CDFS 9 0.69 CDO 20 1.53 CDOPT 11 1.12
CDP 6 0.46 124 12.63 CDPS 7 0.53 31 3.16 CDPST 12 1.22 CDPT 66 6.72 CDT 7 0.53
D 676 51.60 187 19.04 DF 108 8.24 DFM 7 0.53 DFP 16 1.22 6 0.61 DFPS 8 0.61
DFPT 10 1.02 DFS 19 1.45 DFT II 0.84 DM 9 0.69 DO 10 0.76
DOP 13 1.32 DOPT 8 0.81 DP 25 1.91 153 15.58 DPS 7 0.53 29 2.95 DPST 5 0.51
DPT 6 0.46 39 3.97 DS 24 1.83 DST 7 0.53 DT 63 4.81
F 9 0.69
FIMOPT 5 0.51 P 64 6.52 PT 5 0.51 S 6 0.46 T 8 0.61
"Each letter in this column represents a particular treatment objective from table 5, e.g. CD is corrosion control combined with disinfection.
/
'
....
Table E2. Multiple Treatment Objectives Found in Large Community Water Systems
Treatment Ground Water Systems Surface Water Systems
Objectives' Number Percent Number Percent
BCDFIMO
BCDFIMOP
BCDP
BCDPT
BCFPST
5 15
8
12
6
0.50
1.50
0.80
1.20
0.60
BDPS 5 0.50 BDPT 16 1.60
CD 56 7.58 20 2.01
CDF 30 4.06
CDFMP 7 0.70
CDFO 8 1.08
CDFP 10 1.35 12 1.20
CDFPST 18 1.81
CDFPT 20 2.01
CDFS 5 0.68
CDIPST 5 0.68
CDO 9 1.22
CDOP 10 1.00 CDOPT 13 1.30 CDP 110 11.03
CDPS 8 1.08 24 2.41
CDPST 6 0.81 17 1.71
CDPT 79 7.92
CDT 15 2.03
D 273 36.94 167 16.75
DF 40 5.41 6 0.60
DFP 6 0.60
DFPT 9 0.90
DFS ' 17 2.30
DFT 6 0.81
DO 18 2.44
DP 11 1.49 99 9.93
DPS 15 2.03 21 2.11
DPST 10 1.35 7 0.70
DPT 44 4.41
DS
DT
P
16
55 2.17
7.44
85 8.53
"Each letter in this column represents a particular treatment objective from table 5,
e.g. CD is corrosion control combined with disinfection.
67
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68
Table E3. Multiple Treatment Objectives Found in Very Large Community Water Systems Treatment Ground Water Systems Surface Water Systems Objectivesa Number Percent Number Percent
CDOPT 6 3.80 CDP 22 13.92 CDPT 15 9.49 D 12 28.57 7 4.43
DP .............._ ......................, __........"".._._..................." .......................................M .................." .......____.......................__.....""......................."._............................." .................._
16 ............." ........
10.13 ............._._-_.._
DPT 11 6.96 P 18 11.39
aEach letter in this column represents a particular treatment objective from table 5,
e.g. CD is corrosion control combined with disinfection. .
I
J J
1
-
APPENDIX F
Summary Tables for CWS's MUltiple Treatment Processes
Exhibit Fl. Codes for Water Treatment Processes
Treatment Process Types
Code Name Included
A Aeration Cascade
DIffused Packed Tower
Slat Tray
Spray
C
E
F
Chlorination
Ion Exchange
Filtration
Chloramines Chlorine Dioxide Pre- and Post-Gaseous Chlorination
Pre- andPost-Hypochlorination
Activated Alumina Ion Exchange
Cartridge Diatomaceous Earth Greensand
Pressure Sand
Rapid Sand Slow Sand Ultrafiltration
H pH Adjustment Pre-and Post-pH Adjustment
I Inhibitors Bimetallic Phosphate
Hexametaphosphate Orthophosphate
Polyphosphate
Silicate
L Lime-Soda Ash
N Activated Carbon Granular Powered
0
P
Ozonation
Permanganate
Pre-and Post-Ozonation
-R Reverse Osmosis
U Ultraviolet Radiation
70
Table Fl. Multiple Treatment Processes Found in Very Small Community Water Systems'
Ground Water Systems
Processes Number Percent
AC 233 2.27
ACE 5 0.05 ACEF 7 0.Q7
ACEP 24 0.23 ACF 56 0.55
ACFH 13 0.13
ACFHINOP 5 0.05 ACFL 5 0.05 ACH 24 0.23
ACHR 12 0.12
AF 13 0.13
AFHP 9 0.09
AFP 57 0.56
AP 46 0.45
C 7984 77.89
CE 246 2.40
CEF 36 0.35
CEH 10 0.10
CEI 9 0.09
CF 267 2.60
CFH 30 0.29
CFHL CFHN
CFHNO 40 0.39
CFHP 5 0.05
CFI 5 0.05
CFL II 0.11 CFN 5 0.05
CFP 12 0.12
CH 374 3.65
CHI 26 0.25 CI 142 1.39 CL 19 0.19 CN 19 0.19
CR 8 0.08
E 110 1.07 EF 8 0.08 EFP 10 0.10 EP 8 0.08 F 108 1.05 ._............__.............._--_........._.._._..__..__........._...._---------FH H 41 0.40
Surface Water Systems
Number Percent
8
251
1.01
31.57
278
41
5 9
34.97
5.16
0.63 1.13
5 14 10
7
0.63
1.76 1.26
0.88
94 11.82 ......__......_.........._......._._......_..._.........................
5 0.63
HP 9 0.09 I 10 0.10 L 25 0.24
N 9 0.09 -0 5 0.05 R 5 0.05 U 18 0.18
"The letters refer to combinations of treatment processes given in Exhibit FI.
71
Table F2. Multiple Treatment Processes Found in Small Community Water Systems" Ground Water Systems Surface Water Systems
Processes Number Percent Number Percent
AC 7 0.46 ACEFI 5 0.10 ACEFIP 7 0.46 ACF 122 2.38 12 0.79 A<:;FH 53 1.04 9 0.59
ACFHL 9 0.18 ACFI 12 0.23 ACFL 19 0.37 ACH 81 1.58 ACHR II 0.21
ACI II 0.21 ACL 6 0.12 AF 28 0.55 AFHP 24 0.47 29 1.91 AFP 47 0.92 16 1.05
AP 15 0.29 C 3394 66.32 423 27.85 CE 23 0.45 CEF 43 0.84 7 0.46 CEH 8 0.16
CEI 5 0.10 CF 165 3.22 332 21.86 CFH 47 0.92 152 10.01 CFHI 18 1.19 CFHIN 5 0.33
CFHL 8 0.16 27 1.78 CFHLN 9 0.59 CFHN 36 2.37
CFHNO 6 0.12 CFHP 17 0.33
CFI II 0.21 40 2.63 CFIL 10 0.66 CFIN 6 0.40 CFL 42 0.82 39 2.57 CFLN 20 1.32
CFN 29 1.91 CFP 18 0.35 CH 215 4.20 20 1.32 CHI 24 0.47 5 0.33 CHL 5 0.33___••••••__••__•••_.____•••••__••••___._._____.0.-.__._••0_..._..._._..........._..._-_._........-.
CI CL CR ECAP EFP
132 43
5 II 5
2.58 0.84 0.10 0.21 0.10
11 9
0.72 0.59
F FHNP FNP H I
12
13 17
0.23
0.25 0.33
124 II 5
II
8.16 0.72 0.33 0.72
-L 39 0.76 5 0.33
"The letters refer to combinations of treatment processes given in Exhibit Fl.
72
Table F3. Multiple Treatment Processes Found in Medium-Size Community Water Systemsa
Ground Water Systems Surface Water Systems Processes Number Percent Number Percent
AC 83 6.36
ACE 5 0.38
ACEFlP 10 1.02
ACF 46 3.52 7 0.71
ACFH 26 1.99 11 1.12
ACFI 14 1.07 • ACFL 11 0.84
ACH 28 2.14
AFHP 21 2.14
AFP 8 0.61 7 0.71
C 752 57.58 194 19.80
CE 12 0.92
CEF 6 0.46
CF 48 3.68 168 17.14
CFH 17 1.30 128 13.06
CFHI 25 2.55
CFHIN 13 1.33
CFHL 6 0.46 14 1.43
CFHLN 6 0.61
CFHN 35 3.57
CFI 33 3.37
CFIN 9 0.92
CFL 13 1.00 17 1.73
CFLN 8 0.82
CFN 31 3.16
CFP 7 0.54
CH 45 3.45 23 2.35
CHI 8 0.61 6 0.61
CI 43 3.29 9 0.92
CL 18 1.38 9 0.92
F 63 6.43 FHNP 17 1.73 FNP 5 0.51 -H 6 0.61 L 5 0.38
~he letters refer to combinations of treatment processes given in Exhibit Fl.
73
Table F4. Multiple Treatment Processes Found in Large Community Water Systemsa
Ground Water Systems Surface Water Systems
Processes Number Percent Number Percent
AC 76 10.30 6 0.60 ACEFIP 11 1.11 ACF 19 2.57 19 1.91 ACFH 29 3.93 12 1.21 ACFHI 6 0.81
ACFHN 9 0.91 ACFI 9 1.22 ACFL 21 2.85
ACH 25 3.39 ACI 5 0.68
AFHP 14 1.41 AFP 8 1.08 6 0.60 C 300 40.65 178 17.91 CE 5 0.68 CEFINP 21 2.11
CEFLNP 8 0.80 CF 17 2.30 114 11.47 CFH 11 1.49 113 11.37
CFHI 38 3.82 CFHIN 25 2.52
CFHL 11 1.11 CFHN 45 4.53
CFI 23 2.31
CFILN 5 0.50
CFIN 17 1.71
CFL 19 2.57 6 0.60 CFLN 10 1.01 CFN 29 2.92 CH 33 4.47 13 1.31
CI 21 2.85 9 0.91
CL 18 2.44 17 1.71 ECAP 6 0.60 F 84 8.45 FHLP 6 0.60 -FHNP 22 2.21
FNP 8 0.80
~he letters refer to combinations of treatment processes given in Exhibit Fl. I
74
Table F5. Multiple Treatment Processes Found in Very Large Community Water Systemsa
Ground Water Systems Surface Water Systems
Processes Number Percent Number Percent \
\ACFH 5 3.16 C 12 28.57 10 6.33 CF 21 13.29 CFH 20 12.66
CFHI , 5 3.16
CFHN 11 6.96 CFN 7 4.43 F 18 11.39 FHNP 7 4.43
aThe letters refer to combinations of treatment processes given in Exhibit Fl. I
-
- - -
APPENDIX G
Summary Tables for CWS's Estimated and Actual Treatment Combinations
Table G I. Estimated Treatment Needs and Actual Treatment Combinations Used by Community Water Systems with a Ground Water Source
Treatment No. of Very Small Small Medium Large Very Large
Combination Treatments Estimated" Actual" Estimated Actual Estimated Actual Estimated Actual Estimated Actual ----- ... ----0/0--- ----- -----
No Treatment 0 14.313 48.213 22.477 21.042 23.840 13.529 25.000 7.422 32.558 1.471
All. Treatment" I 0.379 2.284 0.538 7.117 0.000 9.647 0.000 20.508 0.000 36.765
Disinfection (DSF)d I 10.363 40.125 6.543 50.379 • 4.941 47.706 2.592 31.445 0.000 17.647
Corrosion Control (CC)' I 21.784 0.449 34.135 1.081 35.414 0.706 37.207 0.586 44.186 0.000
Ion Exchange (IEl I 0.792 0.666 1.536 0.154 2.341 0.000 3.763 0.000 2.326 0.000
Aeration (PTAt I 5.020 0.642 3.883 1.319 3.251 0.824 2.926 1.074 2.326 0.000
Gran. Act. Carbon (GAC) 1 1.640 0.058 1.174 0.000 0.607 0.000 0.502 0.000 0.000 0.000
DSF ICC 2 15.364 3.018 9.712 7.875 7.326 9.941 3.930 12.598 0.000 16.176
DSF lIE 2 0.558 1.415 0.430 0.997 0.477 1.176 0.334 0.781 0.000 0.000
DSFI PTA 2 3.540 1.473 1.095 5.348 0.694 8.059 0.251 9.668 0.000 5.882
DSF/GAC 2 1.159 0.121 0.323 0.098 0.130 0.059 0.000 0.293 0.000 1.471
CC/IE 2 1.178 0.019 2.279 0.028 3.511 0.000 5.518 0.000 4.651 0.000
CC/PTA 2 7.443 0.048 5.771 0.365 4.855 0.294 4.264 0.391 2.326 0.000
CC/GAC 2 2.430 0.005 1.731 0.000 0.867 0.059 0.669 0.098 0.000 0.000
lEI PTA 2 0.271 0.010 0.254 0.056 0.303 0.059 0.334 0.000 0.000 0.000
IE/GAC 2 0.086 0.010 0,078 0.000 0.043 0.000 0.000 0.000 0.000 0.000
PTA/GAC 2 0.558 0.000 0.196 0.000 0.087 0.000 0.000 0.000 0.000 0.000
DSF I CC /IE 3 0.829 0.135 0.646 0.239 0.737 0.824 0.585 0.684 0.000 0.000
DSF ICCI PTA 3 5.248 0.309 1.633 3.046 0.997 5.882 0.418 11.621 0.000 14.706
DSF I CC I GAC 3 1.717 0.212 0.489 0.140 0.173 0.176 0.084 0.684 0.000 0.000
DSF / IE/GAC 3 0.000 0.034 0.000 0.154 0.000 0.118 0.000 0.098 0.000 0.000
DSF I IE I PTA 3 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
DSF I PTA I GAC 3 0.395 0.014 0.049 0.028 0.000 0.118 0.000 0.488 0.000 0.000
DSF I PTA I IE 3 0.000 0.116 0.000 0.056 0.000 0.000 0.000 0.195 0.000 0.000
CC/IEI PTA 3 0.401 0.000 0.381 0.028 0.477 0.000 0.585 0.000 0.000 0.000
CC/IE/GAC 3 0.126 0.000 0.117 0.000 0.087 0.000 0.000 0.000 0.000 0.000
CC I PTA IGAC 3 0.829 0.000 0.284 0.000 0.130 0.000 0.084 0.000 0.000 0.000
IE/PTA/GAC 3 0.00 0.00 0.00 0.00 0.00 0.00. 0.00 0.00 0.00 0.00
DSF I CC /IE I PTA 4 0.28 0.02 0.12 0.21 0.09 0.53 0.00 0.68 0.00 0.00
DSF I CC /IE I GAC 4 0.09 0.02 0.03 0.01 0.00 0.00 0.00 0.00 0.00 0.00
DSF I CC I PTA IGAC 4 0.00 0.02 0.00 0.00 0.00 0.06 0.00 0.39 0.00 1.47
Other Combinations; 3.20, 0.55 4.10 0.22 8.63 0.24 10.95 0.29 11.63 4.41
'Estimated percentages were calculated from EPA document, Benefits and Costs of the 1986 Amendments to the SDWA (Wade Miller, 1989).
bActual percentages were obtained from FRDS multiple treatment data search results.
'The number of systems using alternative treatments includes those that do not directly affect SDWA treatment requirements, (e.g. fluoride treatment).
dDisinfection (DSF) includes treatment process codes C, 0, and U. (See Exhibit Fl.)
'Corrosion (CC) control includes treatment process codes I, H, L. (See Exhibit Fl.)
rIon exchange (IE) relates to code E, and includes activated both alumina, and anion and cation exchange.
gAeration (PTA) includes all aeration processes: Cascade, diffused, packed tower, slat spray, and spray aeration.
hGAC includes both powdered and granulated activated carbon processes.
iThis category includes treatment combinations that are not considered feasible and combinations estimated to affect less than one percent of all systems.
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76
Table G2. Estimated Treatment Needs and Actual Treatment Combinations Used by Community Water Systems with a Surface Water Source Treatment No. of Very Small Small Medium Large Very Large
Combination Treatments Estimated' Actualb Estimated Actual Estimated Actual Estimated Actual Estimated Actual ~----- ------ ----%---- ... - - - --- .. -----.
No Treatment 0 11.615 48.837 12.486 22.040 14.965 13.074 15.107 11.972 22.318 3.614
Alt. Treatment' I 1.988 1.194 0.502 2.388 0.000 2.078 0.000 2.412 0.000 1.205
Filtration (FILT)d I 24.907 23.759 25.585 22.736 23.702 20.087 23.605 17.227 16.738 24.096 Corrosion Control (CC)e I 20.186 0.880 19.398 3.831 22.145 5.714 22.403 4.393 33.047 3.614
Ion Exchange (IE)' 1 0.000 0.126 0.000 0.199 0.000 0.260 0.000 0.086 0.000 0.000
Aeration (PTA)" 1 0.000 0.314 0.000 0.398 0.000 0.346 0.000 0.603 0.000 0.602
Gran. Act. Carbon (GAC I 0.248 0.126 0.279 0.149 0.433 0.173 0.515 0.345 0.000 0.000 FILT ICC 2 36.894 5.091 38.071 15.025 35.121 20.173 34.936 18.949 24.893 19.277 FILT I IE 2 0.186 0.251 0.056 0.348 0.000 0.260 0.000 0.000 0.000 0.000 FILT/PTA 2 0.000 0.629 0.000 1.393 0.000 1.212 0.000 2.153 0.000 3.012
FlLT/GAC 2 0.497 0.691 0.613 1.741 0.779 3.117 0.687 3.187 0.000 4.819 CC/IE 2 0.124 0.063 0.000 0.050 0.000 0.173 0.000 0.086 0.000 0.000 CCIPTA 2 0.000 0.063 0.000 0.100 0.000 0.260 0.000 0.345 0.000 0.602 CC/GAC 2 0.435 0.063 0.446 0.050 0.692 0.606 0.773 0.947 0.000 0.602 IE I PTA 2 0.000 0.000 0.000 0.149 0.000 0.519 0.000 0.689 0.000 0.000
IE/GAC 2 0.000 0.126 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 PTA/GAC 2 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 FILT I CCI IE 3 0.248 0.000 0.167 0.199 0.000 0.606 0.000 1.981 0.000 1.205 FILT/CC/PTA 3 0.000 0.189 0.000 2.388 0.000 3.636 0.000 3.101 0.000 4.217 FlLT I CC I GAC 3 0.870 1.131 0.892 4.478 1.125 7.965 1.116 11.456 0.429 19.880
FlLT /IE I GAC 3 0.000 0.063 0.000 0.100 0.000 0.000 0.000 0.172 0.000 0.602
FlLTI PTA I GAC 3 0.000 0.063 0.000 0.100 0.000 0.173 0.000 0.258 0.000 0.602 FlLT/PTA/IE 3 0.000 0.000 0.000 0.000 0.000 0000 0.000 0.086 0.000 0.000 CC/IE/PTA 3 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.086 0.000 0.000 CC/IE/GAC 3 0.000 0.000 0.000 0.100 0.000 0.000 0.000 0.086 0.000 0.000
CC/PTA/GAC 3 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.086 0000 0.000 FlLT I CC /lEI PTA 4 0.000 0.063 0.000 0.398 0.000 1.039 0.000 1.034 0.000 0.000 FILT I CCI lEI GAC 4 0.000 0.063 0.000 0.249 0.000 0.779 0.000 0.947 0.000 3.012 FILT I CC I PTA I GAC 4 0.000 0.000 0.000 0.299 0.000 0.952 0.000 1.723 0.000 3.012
Other Combinations' 1.801 16.216 1.505 21.095 1.038 16.797 0.858 15.590 2.575 6.024
'Estimated percentages were calculated from EPA document, Benefits and Costs of the 1986 Amendments to the SDWA (Wade Miller, 1989).
bActual percentages were obtained from FRDS multipIc treatment data search results.
'Thc number of systems using alternative treatments includes those that do not directly affect SDWA treatment requirements, (e.g. fluoride treatment).
dFiltration includes all filtration processes: Cartridge, greensand, DE, rapid sand, slow sand, ultrafiltration and direct filtration.
'Corrosion (CC) control includes treatment process codes I, H, L. (See Exhibit Fl.)
'Ion exchange (IE) relates to code E, and includes activated both alumina, and anion and cation exchange.
"Aeration (PTA) includes all aeration processes: Cascade, diffused, packed tower, slat spray, and spray aeration.
bGAC includes both powdered and granulated activated carbon processes.
'This category includes treatment combinations that are not considered feasible and combinations estimated to affect less than one percent of all systems.
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ATTACHMENT 1
CWS Multiple Objective Combinations by Population Category and Water Source
Very Small Ground Water Svstems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
B 4 0.0 4 0.0 BCD 2 0.0 6 0.1 BCR 1 0.0 7 0.1 BD 10 0.1 17 0.2 BDEFIMOPRST 1 0.0 18 0.2 BDEIOPRST 1 0.0 19 0.2 BDEORT 1 0.0 20 0.2 BDI 1 0.0 21 0.2 BDIMOPRST 1 0.0 22 0.2 BDIOPRS 1 0.0 23 0.2 BDIPRS 1 0.0 24 0.2 BDOT 1 0.0 25 0.2 BEIORST 1 0.0 26 0.3 BIRS 1 0.0 27 0.3 C 47 0.5 74 0.7 CD 495 4.8 569 5.5 CDEI 1 0.0 570 5.5 CDF 51 0.5 621 6.0 CDFI 2 0.0 623 6.0 CDFIMPT 1 0.0 624 6.0 CDFM 30 0.3 654 6.3 CDFMP 2 0.0 656 6.4 CDFMR 1 0.0 657 6.4 CDFMS 1 0.0 658 6.4 CDFO 2 0.0 660 6.4 CDFOP 1 0.0 661 6.4 CDFP 7 0.1 668 6.5 CDFPS 1 0.0 669 6.5 CDFS 5 0.0 674 6.5 CDFT 1 0.0 675 6.5 CDI 9 0.1 684 6.6 CDIPT 1 0.0 685 6.6 CDIST 3 0.0 688 6.7 CDM 4 0.0 692 6.7 CDMS 1 0.0 693 6.7 CDO 19 0.2 712 6.9 CDOP 1 0.0 713 6.9 CDOT 3 0.0 716 6.9 CDP 6 0.1 722 7.0 CDPS 3 0.0 725 7.0 CDPST 4 0.0 729 7.1 CDPT 1 0.0 730 7.1 CDR 3 0.0 733 7.1 CDS 14 0.1 747 7.2 CDST 5 0.0 752 7.3 CDT 5 0.0 757 7.3 CF 6 0.1 763 7.4 CFM 1 0.0 764 7.4 CFMS 1 0.0 765 7.4 CFR 1 0.0 766 7.4 -CM 1 0.0 767 7.4 CO 1 0.0 768 7.4 pv
CPS 1 0.0 769 7.4 CS 3 0.0 772 7.5 D 7506 72.7 8278 80.2 DEF 1 0.0 8279 80.2
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78
Very Small Ground Water Systems (continued)Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent ;.
!
DEFMT 1 0.0 8280 80.2 DEIS 1 0.0 8281 80.2 DET 1 0.0 8282 80.2 DF 380 3.7 8662 83.9 DFI 4 0.0 8666 83.9 DFIM 4 0.0 8670 84.0 DFIMST 1 0.0 8671 84.0 DFIP 1 0.0 8672 84.0 DFIPR 1 0.0 8673 84.0 DFIRS 1 0.0 8674 84.0 DFIS 1 0.0 8675 84.0 DFM 189 1.8 8864 85.8 DFMO 1 '0.0 8865 85.9 DFMOT 2 0.0 8867 85.9 DFMP 6 0.1 8873 85.9 DFMPS 2 0.0 8875 86.0 DFMPT 1 0.0 8876 86.0 DFMS 6 0.1 8882 86.0 DFMT 4 0.0 8886 86.1 DFO 4 0.0 8890 86.1 DFOP 3 0.0 8893 86.1 DFOST 1 0.0 8894 86.1 DFOT 1 0.0 8895 86.2 DFP 33 0.3 8928 86.5 DFPR 4 0.0 8932 86.5 DFPS 6 0.1 8938 86.6 DFPST 3 0.0 8941 86.6 DFPT 14 0.1 8955 86.7 DFRS 1 0.0 8956 86.7 DFS 56 0.5 9012 87.3 DFST 3 0.0 9015 87.3 DFT 20 0.2 9035 87.5 DI 25 0.2 9060 87.7 DIM 10 0.1 9070 87.8 DIO 1 0.0 9071 87.9 DIORST 2 0.0 9073 87.9 DIP 3 0.0 9076 87.9 DIPS 4 0.0 9080 87.9 DIPT 2 0.0 9082 88.0 DIRS 2 0.0 9084 88.0 DIS 5 0.0 9089 88.0 DIST 1 0.0 9090 88.0 DM 64 0.6 9154 88.7 DMPS 1 0.0 9155 88.7 DMT 1 0.0 9156 88.7 DO 16 0.2 9172 88.8 DOP 3 0.0 9175 88.9 DOS 1 0.0 9176 88.9 DOST 1 0.0 9177 88.9 DOT 49 0.5 9226 89.4 DP 109 1.1 9335 90.4 DPR 1 0.0 9336 90.4 DPS 14 0.1 9350 90.6 DPST 4 0.0 9354 90.6 DPT 10 0.1 9364 90.7 DR 2 0.0 9366 90.7 DRS 2 0.0 9368 90.7 DS 224 2.2 9592 92.9 DST 15 0.1 9607 93.0 DT 239 2.3 9846 95.4 E 1 0.0 9847 95.4
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.J
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79
Very Small Ground Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
EFM 2 0.0 9849 95.4 F 130 1.3 9979 96.6 FI 1 0.0 9980 96.7 FIM 2 0.0 9982 96.7 FM 21 0.2 Hio03 96.9 FMO 1 0.0 10004 96.9 FMP 1 0.0 10005 96.9 FMPST 1 0.0 10006 96.9 FMR 1 0.0 10007 96.9 FMS 1 0.0 10008 96.9 FMT 1 0.0 10009 96.9 FOP 2 0.0 10011 97.0 FOST 1 e.o 10012 97.0 FP 9 0.1 10021 97.1 FPS 2 0.0 10023 97.1 FR 1 0.0 10024 97.1 FS 9 0.1 10033 97.2 FT 1 0.0 10034 97.2 I 15 0.1 10049 97.3 IP 1 0.0 10050 97.3 IRS 5 0.0 10055 97.4 IS 1 0.0 10056 97.4 1ST 1 0.0 10057 97.4 M 19 0.2 10076 97.6 0 6 0.1 10082 97.6 OPST 1 0.0 10083 97.7 P 81 0.8 10164 98.4 PS 3 0.0 10167 98.5 PT 1 0.0 10168 98.5 R 7 0.1 10175 98.5 RT 1 0.0 10176 98.6 S 116 1.1 10292 99.7 ST 1 0.0 10293 99.7 T 32 0.3 10325 100.0
Very Small Surface Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BCDFIMOP 1 0.1 1 0.1 BCDIOPRS 1 0.1 2 0.3 BCOP 1 0.1 3 0.4 BDEFIMOS 1 0.1 4 0.5 BDFIOP 1 0.1 5 0.6 BDFIOPST 1 0.1 6 0.8 BDFIPT 1 0.1 7 0.9 BDFPT 1 0.1 8 1.0 BDIOPRS 3 0.4 11 1.4 BDOPT 1 0.1 12 1.5 BDP 2 0.3 14 1.8 C 1 0.1 15 1.9 CD 8 1.0 23 2.9 CDF 1 0.1 24 3.0 CDFIOPT 1 0.1 25 3.1 CDFMP 2 0.3 27 3.4 CDFOPT 2 0.3 29 3.6 CDFP 2 0.3 31 3.9 CDFPR 2 0.3 33 4.1 CDFPST 1 0.1 34 4.3
-1
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80
Very Small Surface Water SYstems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
CDIOPT 1 0.1 35 CDIP 2 0.3 37 CDOP 2 0.3 39 CDOPT 4 0.5 43 CDP 26 3.3 69 CDPS 12 1.5 81 CDPST 1 0.1 82 CDPT 8 1.0 90 CDS 2 0.3 92 CMP 1 0.1 93 CP 1 0.1 94 CPR 1 0.1 95 CPS 5 0.6 100 CRT 1 0.1 101 CS 1 0.1 102 D 237 29.7 339 DEI 1 0.1 340 DEPST 1 0.1 341 DF 6 0.8 347 DFIMOPS 1 0.1 348 DFM 2 0.3 350 DFOPT 2 0.3 352 DFP 3 0.4 355 DFPR 4 0.5 359 DFPS 2 0.3 361 DFPT 1 0.1 362 DFS 1 0.1 363 DFT 1 0.1 364 DI 2 0.3 366 DIO 1 0.1 367 DIOPT 2 0.3 369 DIP 2 0.3 371 DIPT 1 0.1 372 DIS 1 0.1 373 DOP 10 1.3 383 DOPT 3 0.4 386 DOT 5 0.6 391 DP 262 32.8 653 DPR 3 0.4 656 DPS 23 2.9 679 DPST 2 0.3 681 DPT 10 1.3 691 DS 2 0.3 693 DT 7 0.9 700 F 4 0.5 704 P 93 11. 6 797 S 1 0.1 798 T 1 0.1 799
Small Ground Water Systems Treatment Cumulative Objectives Frequency Percent Frequency
BCD 3 0.1 3 BCFPST 1 0.0 4 BD 1 0.0 5 BDF 1 0.0 6 BDFMST 1 0.0 7 BDIOPRST 1 0.0 8
4.4 4.6 4.9 5.4 8.6
10.1 10.3 11.3 11. 5 11.6 11. 8 11. 9 12.5 12.6 12.8 42.4 42.6 42.7 43.4 43.6 43.8 44.1 44.4 44.9 45.2 45.3 45.4 45.6 45.8 45.9 46.2 46.4 46.6 46.7 47.9 48.3 48.9 81. 7 82.1 85.0 85.2 86.5 86.7 87.6 88.1 99.7 99.9
100.0
Cumulative Percent
0.1 -0.1 0.1 0.1 0.1 0.2
---------------------------------------------------------
81
Small Ground Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BDIPRS 2 0.0 10 0.2 C 25 0.5 35 0.7 CD 343 6.7 378 7.3 CDF 102 2.0 480 9.3 CDFIOS 1 0.0 481 9.3 CDFIP 1 0.0 482 9.3 CDFIPS 1 0.0 483 9.4 CDFM 26 0.5 509 9.9 CDFMOP 2 0.0 511 9.9 CDFMOT 1 0.0 512 9.9 CDFMPT 2 0.0 514 10.0 CDFMS 1 0.0 515 10.0 CDFMT 1 0:0 516 10.0 CDFO 27 0.5 543 10.5 CDFOP 2 0.0 545 10.6 CDFP 17 0.3 562 10.9 CDFPS 8 0.2 570 11.1 CDFPST 2 0.0 572 11.1 CDFPT 7 0.1 579 11.2 CDFR 1 0.0 580 11.2 CDFRST 1 0.0 581 11.3 CDFS 11 0.2 592 11. 5 CDFST 1 0.0 593 11. 5 CDFT 5 0.1 598 11.6 CDI 7 0.1 605 11. 7 CDIPST 1 0.0 606 11. 8 CDIPT 2 0.0 608 11.8 CDIS 1 0.0 609 11. 8 CDIST 3 0.1 612 11. 9 CDIT 2 0.0 614 11. 9 CDM 2 0.0 616 11. 9 CDMO 1 0.0 617 12.0 CDMS 1 0.0 618 12.0 CDO 72 1.4 690 13 .4 CDOPT 1 0.0 691 13 .4 CDOT 1 0.0 692 13 .4 CDP 6 0.1 698 13.5 CDPRST 1 0.0 699 13.6 CDPS 7 0.1 706 13.7 CDPST 10 0.2 716 13.9 CDPT 1 0.0 717 13.9 CDRT 2 0.0 719 13 .9 CDS 14 0.3 733 14 .2 CDST 5 0.1 738 14.3 CDT 13 0.3 751 14.6 CF 3 0.1 754 14.6 CFIPS 1 0.0 755 14.6 CFM 3 0.1 758 14.7 CFMP 1 0.0 759 14.7 CFMPST 1 0.0 760 14.7 CFS 1 0.0 761 14.8 CIM 1 0.0 762 14.8 CM 1 0.0 763 14.8 CS 3 0.1 766 14.9 D 3114 60.4 3880 75.2 DEFP 1 0.0 3881 75.3 DF 375 7.3 4256 82.5 DFI 5 0.1 4261 82.6 t -
DFIMO 1 0.0 4262 82.6 DFIMP 2 0.0 4264 82.7 DFIMS 1 0.0 4265 82.7
---------------------------------------------------------
82 .
Small Ground Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
DFIO 1 0.0 4266 82.7 DFIP 1 0.0 4267 82.7 DFIPS 1 0.0 4268 82.8 DFIPST 1 0.0 4269 82.8 DFIS 4 0.1 4273 82.9 DFIST 1 0.0 4274 82.9 DFM 90 1.7 4364 84.6 DFMOP 1 0.0 4365 84.6 DFMP 5 0.1 4370 84.7 DFMS 5 0.1 4375 84.8 DFMST 1 0.0 4376 84.9 DFMT 2 0.0 4378 84.9 DFO 6 0:1 4384 85.0 DFOP 2 0.0 4386 85.0 DFOT 1 0.0 4387 85.1 DFP 39 0.8 4426 85.8 DFPS 13 0.3 4439 86.1 DFPST 4 0.1 4443 86.2 DFPT 11 0.2 4454 86.4 DFRST 2 0.0 4456 86.4 DFRT 1 0.0 4457 86.4 DFS 110 2.1 4567 88.6 DFST 10 0.2 4577 88.8 DFT 24 0.5 4601 89.2 DI 3 0.1 4604 89.3 DIM 1 0.0 4605 89.3 DIP 5 0.1 4610 89.4 DIPS 1 0.0 4611 89.4 DIPT 2 0.0 4613 89.5 DIS 1 0.0 4614 89.5 DIT 3 0.1 4617 89.5 DM 15 0.3 4632 89.8 DMO 1 0.0 4633 89.8 DMOT 1 0.0 4634 89.9 DMP 2 0.0 4636 89.9 DMS 1 0.0 4637 89.9 DMT 2 0.0 4639 90.0 DO 16 0.3 4655 90.3 DOP 3 0.1 4658 90.3 DOPS 1 0.0 4659 90.3 DOS 2 0.0 4661 90.4 DOST 1 0.0 4662 90.4 DOT 11 0.2 4673 90.6 DP 35 0.7 4708 91. 3 DPS 8 0.2 4716 91.4 DPST 13 0.3 4729 91. 7 DPT 15 0.3 4744 92.0 DR 1 0.0 4745 92.0 DS 48 0.9 4793 92.9 DST 14 0.3 4807 93.2 DT 189 3.7 4996 96.9 F 65 1.3 5061 98.1 FM 8 0.2 5069 98.3 FMP 1 0.0 5070 98.3 FOP 2 0.0 5072 98.4 FP 3 0.1 5075 98.4 FPS 1 0.0 5076 98.4 FS 7 0.1 5083 98.6 FT 2 0.0 5085 98.6 M 9 0.2 5094 98.8 MT 2 0.0 5096 98.8
J
) I
-,.......
83
Small Ground Water SYstems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
0 1 0.0 5097 98.8 OPT 1 0.0 5098 98.9 P 6 0.1 5104 99.0 PST 1 0.0 5105 99.0 S 44 0.9 5149 99.8 T 8 0.2 5157 100.0
Small Surface Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent -----------------------------T------------------------- __
BCDFIMO 2 0.1 2 0.1 BCDFIMOP 6 0.4 8 0.5 BCDFIMOPR 3 0.2 11 0.7 BCDFIOP 1 0.1 12 0.8 BCDFP 1 0.1 13 0.9 BCDIMOPT 1 0.1 14 0.9 BCDIOPRS 3 0.2 17 1.1 BCDIOPRST 1 0.1 18 1.2 BCDIOPT 1 0.1 19 1.2 BCDOPT 1 0.1 20 1.3 BCDP 1 0.1 21 1.4 BCDPT 1 0.1 22 1.4 BCFMOPT 1 0.1 23 1.5 BDFIPT 1 0.1 24 1.6 BDFPS 1 0.1 25 1.6 BDFPT 1 0.1 26 1.7 BDFS 1 0.1 27 1.8 BDIOPRS 7 0.5 34 2.2 BDIOPRST 1 0.1 35 2.3 BDIOPST 1 0.1 36 2.4 BDP 7 0.5 43 2.8 BDPS 15 1.0 58 3.8 BDPT 1 0.1 59 3.9 BDS 2 0.1 61 4.0 C 10 0.7 71 4.7 CD 31 2.0 102 6.7 CDFIMOP 1 0.1 103 6.8 CDFIMOPT 3 0.2 106 7.0 CDFIMPST 1 0.1 107 7.0 CDFIOPT 1 0.1 108 7.1 CDFIP 1 0.1 109 7.2 CDFIPT 2 0.1 111 7.3 CDFM 1 0.1 112 7.4 CDFMO 1 0.1 113 7.4 CDFMOP 1 0.1 114 7.5 CDFMP 2 0.1 116 7.6 CDFOP 3 0.2 119 7.8 CDFP 7 0.5 126 8.3 CDFPS 2 0.1 128 8.4 CDFPST 14 0.9 142 9.3 CDFPT 11 0.7 153 10.1 CDIMPT 1 0.1 156 10.3 CDIOPS 1 0.1 157 10.3 -CDIOPT 2 0.1 159 10.5 CDOP 4 0.3 163 10.7 .'
CDOPST 2 0.1 165 10.8 CDOPT 7 0.5 172 11.3 CDFST 1 0.1 154 10.1
----------------------------------------------------------
84
Small Surface Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
CDIM 1 0.1 155 10.2 CDP 130 8.5 302 19.9 CDPR 1 0.1 303 19.9 CDPRT 1 0.1 304 20.0 CDPS 64 4.2 368 24.2 CDPST 10 0.7 378 24.9 CDPT 39 2.6 417 27.4 CDS 5 0.3 422 27.7 CDT 4 0.3 426 28.0 CF 1 0.1 427 28.1 CFPST 1 0.1 428 28.1 CFPT 1 0.1 429 28.2 CP 3 0.2 432 28.4 CPS 4 0.3 436 28.7 CPST 1 0.1 437 28.7 CT 1 0.1 438 28.8 D 402 26.4 840 55.2 DF 9 0.6 849 55.8 DFIMPST 1 0.1 850 55.9 DFIOP 1 0.1 851 56.0 DFIOPT 1 0.1 852 56.0 DFM 5 0.3 857 56.3 DFOP 2 0.1 859 56.5 DFOPT 1 0.1 860 56.5 DFP 12 0.8 872 57.3 DFPS 10 0.7 882 58.0 DFPST 2 0.1 884 58.1 DFPT 26 1.7 910 59.8 DFRS 1 0.1 911 59.9 DFS 2 0.1 913 60.0 DI 1 0.1 914 60.1 DIOP 1 0.1 915 60.2 DIOPS 1 0.1 916 60.2 DIP 5 0.3 921 60.6 DIPS 4 0.3 925 60.8 DIPST 1 0.1 926 60.9 DIPT 3 0.2 929 61.1 DM 1 0.1 930 61.1 DOP 17 1.1 947 62.3 DOPS 2 0.1 949 62.4 DOPST 1 0.1 950 62.5 DOPT 11 0.7 961 63.2 DOT 2 0.1 963 63.3 DP 298 19.6 1261 82.9 DPS 50 3.3 1311 86.2 DPST 7 0.5 1318 86.7 DPT 47 3.1 1365 89.7 DS 9 0.6 1374 90.3 DT 12 0.8 1386 91.1 FOPT 1 0.1 1387 91. 2 FP 1 0.1 1388 91. 3 lOP 1 0.1 1389 91. 3 OP 1 0.1 1390 91.4 P 123 8.1 1513 99.5 S T
7 1
0.5 0.1
1520 1521
99.9 100.0 -
----------------------------------------------------------
85
Medium Ground Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BCD 1 0.1 1 0.1 BCDFIPST 1 0.1 2 0.2 BCDFMS 1 0.1 3 0.2 BCFMOPT 1 0.1 4 0.3 BDFIMOPRST 1 0.1 5 0.4 BDFMST 1 0.1 6 0.5 BDS 1 0.1 7 0.5 C 5 0.4 12 0.9 CD 80 6.1 92 7.0 CDF 39 3.0 131 10.0 CDFI 4 0.3 135 10.3 CDFIM 1 0.1 136 10.4 CDFM 9 G.7 145 11.1 CDFMO 1 0.1 146 11.1 CDFMOP 5 0.4 151 11. 5 CDFMOS 1 0.1 152 11. 6 CDFMPT 1 0.1 153 11. 7 CDFMS 3 0.2 156 11. 9 CDFMT 1 0.1 157 12.0 CDFO 6 0.5 163 12.4 CDFOP 1 0.1 164 12.5 CDFP 6 0.5 170 13.0 CDFPRST 1 0.1 171 13.1 CDFPS 4 0.3 175 13.4 CDFPST 3 0.2 178 13.6 CDFPT 2 0.2 180 13.7 CDFS 9 0.7 189 14.4 CDFST 2 0.2 191 14.6 CDFT 4 0.3 195 14.9 CDI 1 0.1 196 15.0 CDIP 1 0.1 197 15.0 CDIPT 1 0.1 198 15.1 CDM 2 0.2 200 15.3 CDO 20 1.5 220 16.8 CDOP 1 0.1 221 16.9 CDOS 1 0.1 222 16.9 CDP 6 0.5 228 17.4 CDPS 7 0.5 235 17.9 CDPST 2 0.2 237 18.1 CDPT 3 0.2 240 18.3 CDS 1 0.1 241 18.4 CDST 1 0.1 242 18.5 CDT 7 0.5 249 19.0 CF 1 0.1 250 19.1 CT 1 0.1 251 19.2 D 676 51. 6 927 70.8 DF 108 8.2 1035 79.0 DFI 2 0.2 1037 79.2 DFIM 1 0.1 1038 79.2 DFIMPT 1 0.1 1039 79.3 DFIP 1 0.1 1040 79.4 DFM 7 0.5 1047 79.9 DFMOP 1 0.1 1048 80.0 DFMP 2 0.2 1050 80.2 DFMS DFMST
1 1
0.1 0.1
1051 1052
80.2 80.3 -DFMT 2 0.2 1054 80.5
DFO 2 0.2 1056 80.6 DFP 16 1.2 1072 81. 8 DFPS 8 0.6 1080 82.4 DFPST 1 0.1 1081 82.5
----------------------------------------------------------
----------------------------------------------------------
86
Medium Ground Water SYstems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
DFPT 1 0.1 1082 82.6 DFR 1 0.1 1083 82.7 DFS 19 1.5 1102 84.1 DFST 1 0.1 1103 84.2 DFT 11 0.8 1114 85.0 DI 2 0.2 1116 85.2 DIPS 1 0.1 1117 85.3 DIS 1 0.1 1118 85.3 DM 9 0.7 1127 86.0 DO 10 0.8 1137 86.8 DOPST 1 0.1 1138 86.9 DOS 1 0.1 1139 86.9 DOT 4 0.3 1143 87.3 DP 25 1.9 1168 89.2 DPS 7 0.5 1175 89.7 DPST 4 0.3 1179 90.0 DPT 6 0.5 1185 90.5 DR 1 0.1 1186 90.5 DRT 1 0.1 1187 90.6 DS 24 1.8 1211 92.4 DST 7 0.5 1218 93.0 DT 63 4.8 1281 97.8 F 9 0.7 1290 98.5 FM 1 0.1 1291 98.5 FMS 1 0.1 1292 98.6 FS 1 0.1 1293 98.7 M 1 0.1 1294 98.8 P 2 0.2 1296 98.9 S 6 0.5 1302 99.4 T 8 0.6 1310 100.0
Medium Surface Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BCDFIMO 1 0.1 1 0.1 BCDFIMOP 9 0.9 10 1.0 BCDFIMOPR 1 0.1 11 1.1 BCDFIMOPRT 1 0.1 12 1.2 BCDFIMOPT 1 0.1 13 1.3 BCDFIOPR 3 0.3 16 1.6 BCDFIOPRST 1 0.1 17 1.7 BCDFIOPT 1 0.1 18 1.8 BCDFPT 6 0.6 24 2.4 BCDFT 1 0.1 25 2.5 BCDIOP 1 0.1 26 2.6 BCDIOPRST 1 0.1 27 2.7 BCDIOPST 1 0.1 28 2.9 BCDP 2 0.2 30 3.1 BCDPT 1 0.1 31 3.2 BCFP 1 0.1 32 3.3 BCFPST 1 0.1 33 3.4 BCIOPRS 3 0.3 36 3.7 BD 1 0.1 37 3.8 BDFIMOPRS 2 0.2 39 4.0 BDFIOP 1 0.1 40 4.1 BDFIOPRS 2 0.2 42 4.3 BDFP 1 0.1 43 4.4 BDFPT 1 0.1 44 4.5
-....."
----------------------------------------------------------
87
Medium Surface Water SYstems (continued)Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BDIOPRS 1 0.1 45 4.6 BDIOPRST 1 0.1 46 4.7 BDOPT 1 0.1 47 4.8 BDPS 4 0.4 51 5.2 BDPST 2 0.2 53 5.4 BDPT 1 0.1 54 5.5 BF 1 0.1 55 5.6 C 4 0.4 59 6.0 CD 30 3.1 89 9.1 CDEPS 1 0.1 90 9.2 CDF 3 0.3 93 9.5 CDFIMOPST 1 0.1 94 9.6 CDFIMOPT 6 0.6 100 10.2 CDFIP 1 0.1 101 10.3 CDFM 2 0.2 103 10.5 CDFMOP 1 0.1 104 10.6 CDFMP 1 0.1 105 10.7 CDFOP 1 0.1 106 10.8 CDFOPT 3 0.3 109 11.1 CDFP 8 0.8 117 11. 9 CDFPS 1 0.1 118 12.0 CDFPST 8 0.8 126 12.8 CDFPT 16 1.6 142 14.5 CDFS 1 0.1 143 14.6 CDIOP 2 0.2 145 14.8 CDIOPS 1 0.1 146 14.9 CDIP 1 0.1 147 15.0 CDIPS 1 0.1 148 15.1 CDIPT 1 0.1 149 15.2 CDMOPT 1 0.1 150 15.3 CDMP 2 0.2 152 15.5 CDOP 4 0.4 156 15.9 CDOPT 11 1.1 167 17.0 CDOS 1 0.1 168 17.1 CDP 124 12.6 292 29.7 CDPS 31 3.2 323 32.9 CDPST 12 1.2 335 34.1 CDPT 66 6.7 401 40.8 CDS 2 0.2 403 41. 0 CDT 4 0.4 407 41.4 CIMOPT 1 0.1 408 41. 5 CPS 2 0.2 410 41.8 CPST 1 0.1 411 41. 9 D 187 19.0 598 60.9 DE 1 0.1 599 61. 0 DF 2 0.2 601 61.2 DFIMOP 1 0.1 602 61.3 DFIOPT 2 0.2 604 61.5 DFM 1 0.1 605 61.6 DFMP 1 0.1 606 61. 7 DFOPT 2 0.2 608 61. 9 DFP 6 0.6 614 62.5 DFPS 4 0.4 618 62.9 DFPST 2 0.2 620 63.1 DFPT 10 1.0 630 64.2 DI 1 0.1 631 64.3 -DIMOP 1 0.1 632 64.4 DIOPT 1 0.1 633 64.5 DIP 2 0.2 635 64.7 DIPS 1 0.1 636 64.8 DIPT 2 0.2 638 65.0
,.
----------------------------------------------------------
---------------------------------------------------------
88
Medium. Surface Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
DMP 1 0.1 639 65.1 DMPT 1 0.1 640 65.2 DOP 13 1.3 653 66.5 DOPST 1 0.1 654 66.6 DOPT 8 0.8 662 67.4 DOT 1 0.1 663 67.5 DP 153 15.6 816 83.1 DPS 29 3.0 845 86.0 DPST 5 0.5 850 86.6 DPT 39 4.0 889 90.5 DS 2 0.2 891 90.7 DST 1 0.1 892 90.8 DT 3 Cl.3 895 91.1 FIMOPT 5 0.5 900 91.6 FlOPS 1 0.1 901 91. 8 FIT 1 0.1 902 91. 9 FP 1 0.1 903 92.0 FPT 1 0.1 904 92.1 I 1 0.1 905 92.2 IMOPT 1 0.1 906 92.3 lOP 1 0.1 907 92.4 OP 1 0.1 908 92.5 P 64 6.5 972 99.0 PS 2 0.2 974 99.2 PST 1 0.1 975 99.3 PT 5 0.5 980 99.8 S 2 0.2 982 100.0
Large Ground Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BCDF 3 0.4 3 0.4 BCDFIOPS 1 0.1 4 0.5 BCDFO 1 0.1 5 0.7 BDIOPT 1 0.1 6 0.8 C 3 0.4 9 1.2 CD 56 7.6 65 8.8 CDF 30 4.1 95 12.9 CDFI 2 0.3 97 13.1 CDFIMP 1 0.1 98 13.3 CDFIP 1 0.1 99 13.4 CDFIPT 1 0.1 100 13 .5 CDFMO 4 0.5 104 14.1 CDFMOP 2 0.3 106 14.3 CDFMOPT 1 0.1 107 14.5 CDFMPS 1 0.1 108 14.6 CDFMS 1 0.1 109 14.7 CDFMT 1 0.1 110 14.9 CDFO 8 1.1 118 16.0 CDFOP 1 0.1 119 16.1 CDFOPS 1 0.1 120 16.2 CDFOPT 1 0.1 121 16.4 CDFOT 1 0.1 122 16.5 CDFP 10 1.4 132 17.9 CDFPS 4 0.5 136 18.4 CDFPST 4 0.5 140 18.9 CDFPT 3 0.4 143 19.4 CDFS 5 0.7 148 20.0
I I
J -
J
---------------------------------------------------------
Large Ground Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
CDFST 1 0.1 149 20.2 CDFT 4 0.5 153 20.7 CDIO 1 0.1 154 20.8 CDIP 1 0.1 155 21. 0 CDIPST 5 0.7 160 21.7 CDIT 1 0.1 161 21.8 CDO 9 1.2 170 23.0 CDOP 1 0.1 171 23.1 CDOPRS 1 0.1 172 23.3 CDOPT 4 0.5 176 23.8 CDOS 1 0.1 177 24.0 CDOST 1 0.1 178 24.1 CDOT 1 0 . .1 179 24.2 CDP 1 0.1 180 24.4 CDPS 8 1.1 188 25.4 CDPST 6 0.8 194 26.3 CDPT 3 0.4 197 26.7 CDR 1 0.1 198 26.8 CDS 3 0.4 201 27.2 CDST 3 0.4 204 27.6 CDT 15 2.0 219 29.6 CIPST 1 0.1 220 29.8 CP 1 0.1 221 29.9 CT 1 0.1 222 30.0 D 273 36.9 495 67.0 DEFP 1 0.1 496 67.1 DF 40 5.4 536 72.5 DFIS 1 0.1 537 72.7 DFM 3 0.4 540 73.1 DFMP 1 0.1 541 73.2 DFMPS 1 0.1 542 73.3 DFMPT 2 0.3 544 73.6 DFMS 1 0.1 545 73.7 DFMT 1 0.1 546 73.9 DFO 1 0.1 547 74.0 DFP 4 0.5 551 74.6 DFPS 4 0.5 555 75.1 DFPST 1 0.1 556 75.2 DFPT 3 0.4 559 75.6 DFS 17 2.3 576 77.9 DFST 1 0.1 577 78.1 DFT 6 0.8 583 78.9 DI 1 0.1 584 79.0 DIM 1 0.1 585 79.2 DIOS 1 0.1 586 79.3 DIPT 2 0.3 588 79.6 DIT 1 0.1 589 79.7 DM 3 0.4 592 80.1 DMT 1 0.1 593 80.2 DO 18 2.4 611 82.7 DOPS 1 0.1 612 82.8 DOPST 2 0.3 614 83.1 DOPT 1 0.1 615 83.2 DOS 1 0.1 616 83.4 DOST DOT
1 2
0.1 0.3
617 619
83.5 83.8
DP 11 1.5 630 85.3 DPS 15 2.0 645 87.3 r", DPST 10 1.4 655 88.6 DPT 1 0.1 656 88.8 DRT 1 0.1 657 88.9
-
-
-----------------------------------------------------------
90
Large Ground Water SYstems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
DS 16 2.2 673 91.1 DST 1 0.1 674 91.2 DT 55 7.4 729 98.6 F 3 0.4 732 99.1 FMP 1 0.1 733 99.2 IMT 1 0.1 734 99.3 0 1 0.1 735 99.5 P 2 0.3 737 99.7 S 1 0.1 738 99.9 T 1 0.1 739 100.0
Large Surface Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
B 3 0.3 3 0.3 BCDEFIOPT 1 0.1 4 0.4 BCDEOPT 1 0.1 5 0.5 BCDEP 1 0.1 6 0.6 BCDFIM 1 0.1 7 0.7 BCDFIMO 5 0.5 12 1.2 BCDFIMOP 15 1.5 27 2.7 BCDFIMOPR 2 0.2 29 2.9 BCDFIMOPRST 1 0.1 30 3.0 BCDFIMOPST 1 0.1 31 3.1 BCDFIMOPT 1 0.1 32 3.2 BCDFIMPT 1 0.1 33 3.3 BCDFOP 1 0.1 34 3.4 BCDFOPT 1 0.1 35 3.5 BCDFP 2 0.2 37 3.7 BCDFPS 2 0.2 39 3.9 BCDFPT 3 0.3 42 4.2 BCDIMOPT 1 0.1 43 4.3 BCDIOP 1 0.1 44 4.4 BCDIOPRS 1 0.1 45 4.5 BCDIOPRST 2 0.2 47 4.7 BCDOP 1 0.1 48 4.8 BCDOPST 1 0.1 49 4.9 BCDOPT 2 0.2 51 5.1 BCDP 8 0.8 59 5.9 BCDPS 2 0.2 61 6.1 BCDPST 2 0.2 63 6.3 BCDPT 12 1.2 75 7.5 BCFPST 6 0.6 81 8.1 BD 2 0.2 83 8.3 BDFPS 1 0.1 84 8.4 BDFPT 2 0.2 86 8.6 BDOPS 1 0.1 87 8.7 BDOPT 2 0.2 89 8.9 BDOST 1 0.1 90 9.0 BDP 3 0.3 93 9.3 BDPS 5 0.5 98 9.8 BDPST 2 0.2 100 10.0 BDPT 16 1.6 116 11. 6 BDS 2 0.2 118 11. 8 BDT 2 0.2 120 12.0 BP 1 0.1 121 12.1 C 2 0.2 123 12.3 CD 20 2.0 143 14.3
r
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II,,
-
-----------------------------------------------------------
91
Large Surface Water SYstems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
CDF 2 0.2 145 14.5 CDFI 1 0.1 146 14.6 CDFIM 1 0.1 147 14.7 CDFIMOP 1 0.1 148 14.8 CDFIMOPR 1 0.1 149 14.9 CDFIMOPT 2 0.2 151 15.1 CDFIMS 1 0.1 152 15.2 CDFIOP 1 0.1 153 15.3 CDFIOPRT 1 0.1 154 15.4 CDFIOPT 1 0.1 155 15.5 CDFIP 1 0.1 156 15.6 CDFIPT 1 0.1 157 15.7 CDFMOP 3 ·0.3 160 16.0 CDFMOPT 2 0.2 162 16.2 CDFMP 7 0.7 169 17.0 CDFMPT 1 0.1 170 17.1 CDFOP 3 0.3 173 17.4 CDFOPS 1 0.1 174 17.5 CDFOPT 3 0.3 177 17.8 CDFP 12 1.2 189 19.0 CDFPS 2 0.2 191 19.2 CDFPST 18 1.8 209 21. 0 CDFPT 20 2.0 229 23.0 CDIOPST 1 0.1 230 23.1 CDIP 2 0.2 232 23.3 CDIPRS 1 0.1 233 23.4 CDIPS 1 0.1 234 23.5 CDIPT 2 0.2 236 23.7 CDIT 1 0.1 237 23.8 CDM 2 0.2 239 24.0 CDMP 3 0.3 242 24.3 CDMPT 2 0.2 244 24.5 CDMT 1 0.1 245 24.6 CDO 1 0.1 246 24.7 CDOP 10 1.0 256 25.7 CDOPS 2 0.2 258 25.9 CDOPT 13 1.3 271 27.2 CDOT 2 0.2 273 27.4 CDP 110 11. 0 383 38.4 CDPS 24 2.4 407 40.8 CDPST 17 1.7 424 42.5 CDPT 79 7.9 503 50.5 CDT 1 0.1 504 50.6 CFMT 1 0.1 505 50.7 CP 1 0.1 506 50.8 CPT 1 0.1 507 50.9 CT 1 0.1 508 51. 0 D 167 16.8 675 67.7 DEPT 1 0.1 676 67.8 DF 6 0.6 682 68.4 DFI 1 0.1 683 68.5 DFIMOPST 1 0.1 684 68.6 DFIMPT 1 0.1 685 68.7 DFIOP 1 0.1 686 68.8 DFIPS DFIPT
1 1
0.1 0.1
687 688
68.9 69.0 -DFM 1 0.1 689 69.1
DFMP 1 0.1 690 69.2 DFOS 2 0.2 694 69.6 DFP 6 0.6 700 70.2
-----------------------------------------------------------
---------------------------------------------------------
92
Large Surface Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
DFPS 2 0.2 702 70.4 DFPST 1 0.1 703 70.5 DFPT 9 0.9 712 71.4 DFS 2 0.2 714 71. 6 DFT 1 0.1 715 71.7 DM 1 0.1 716 71. 8 DO 3 0.3 719 72 .1 DOP 3 0.3 722 72.4 DOPST 2 0.2 724 72.6 DOPT 4 0.4 728 73.0 DOT 1 0.1 729 73.1 DP 99 9.9 828 83.0 DPS 21 2.;1.. 849 85.2 DPST 7 0.7 856 85.9 DPT 44 4.4 900 90.3 DS 4 0.4 904 90.7 DT 2 0.2 906 90.9 F 1 0.1 907 91. 0 FOPT 1 0.1 908 91.1 MT 1 0.1 909 91. 2 0 1 0.1 910 91.3 P 85 8.5 995 99.8 PT 1 0.1 996 99.9 T 1 0.1 997 100.0
Very Large Ground Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
CDF 3 7.1 3 7.1 CDFP 1 2.4 4 9.5 CDFPS 1 2.4 5 11. 9 CDFPT 1 2.4 6 14.3 CDFS 1 2.4 7 16.7 CDOPS 1 2.4 8 19.0 CDOPT 1 2.4 9 21.4 CDOT 1 2.4 10 23.8 CDPS 3 7.1 13 31. 0 CDPT 1 2.4 14 33.3 CDS 1 2.4 15 35.7 CDT 4 9.5 19 45.2 D 12 28.6 31 73.8 DO 2 4.8 33 78.6 DPS 1 2.4 34 81. 0 DPST 2 4.8 36 85.7 DS 1 2.4 37 88.1 DT 2 4.8 39 92.9 P 3 7.1 42 100.0
Very Large Surface Water Systems Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BCDEFMOPT 1 0.6 1 0.6 BCDFIMO 2 1.3 3 1.9 BCDFIMOPRT 1 0.6 4 2.5 BCDFIMOPST 1 0.6 5 3.2
i I I
I
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I
J f
-
----------------------------------------------------------
93
Very Large Surface Water Systems (continued) Treatment Cumulative Cumulative Objectives Frequency Percent Frequency Percent
BCDFIOPST 1 0.6 6 3.8 BCDFP 1 0.6 7 4.4 BCDOPT 1 0.6 8 5.1 BCDPST 2 1.3 10 6.3 BCDPT 3 1.9 13 8.2 BCFPST 1 0.6 14 8.9 BD 1 0.6 15 9.5 BDFOPT 1 0.6 16 10.1 BDPS 1 0.6 17 10.8 BDPT 4 2.5 21 13.3 CD 2 1.3 23 14.6 CDEP 1 0.6 24 15.2 CDFIMOPST 1 (J.6 25 15.8 CDFIOPT 1 0.6 26 16.5 CDFIPT 2 1.3 28 17.7 CDFMOPST 1 0.6 29 18.4 CDFOPT 2 1.3 31 19.6 CDFPS 1 0.6 32 20.3 CDFPST 3 1.9 35 22.2 CDFPT 2 1.3 37 23.4 CDIOPT 1 0.6 38 24.1 CDO 1 0.6 39 24.7 CDOP 2 1.3 41 25.9 CDOPT 6 3.8 47 29.7 CDP 22 13.9 69 43.7 CDPRST 1 0.6 70 44.3 CDPS 1 0.6 71 44.9 CDPST 3 1.9 74 46.8 CDPT 15 9.5 89 56.3 CDS 1 0.6 90 57.0 CDT 1 0.6 91 57.6 D 7 4.4 98 62.0 DF 1 0.6 99 62.7 DFO 1 0.6 100 63.3 DFP 1 0.6 101 63.9 DIPS 2 1.3 103 65.2 DOP 2 1.3 105 66.5 DOPT 2 1.3 107 67.7 DP 16 10.1 123 77.8 DPS 4 2.5 127 80.4 DPST 1 0.6 128 81. 0 DPT 11 7.0 139 88.0 DT 1 0.6 140 88.6 P 18 11.4 158 100.0
---------------------------------------------------------
ATTACHMENT 2 )
,ICWS Multiple Treatment Combinations by Population Category and Water Source +
J
Very Small Ground Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
A 17 0.2 17 0.2 )
AC 233 2.3 250 2.4 ACE 5 0.0 255 2.5 ACEF 7 0.1 262 2.6 ACEFlP 2 0.0 264 2.6 ACEH 3 0.0 267 2.6 ACEN 1 0.0 268 2.6 ACEP 24 0.2 292 2.8 ACF 56 0.5 348 3.4 ACFH 13 0.1 361 3.5 ACFHl 1 0.0 362 3.5 ACFHlNOP 5 0.0 367 3.6 ACFHR 1 0.0 368 3.6 ACFl 4 0.0 372 3.6 ACFL 5 0.0 377 3.7 ACFNPR 1 0.0 378 3.7 ACFP 1 0.0 379 3.7 ACFR 2 0.0 381 3.7 ACH 24 0.2 405 4.0 ACHR 12 0.1 417 4.1 ACl 2 0.0 419 4.1 AClP 1 0.0 420 4.1 ACL 1 0.0 421 4.1 ACN 1 0.0 422 4.1 ACP 1 0.0 423 4.1 AE 2 0.0 425 4.1 AEFN 1 0.0 426 4.2 AF 13 0.1 439 4.3 AFHP 9 0.1 448 4.4 AFl 1 0.0 449 4.4 AFP 57 0.6 506 4.9 AP 46 0.4 552 5.4 C 7984 77.9 8536 83.3 CE 246 2.4 8782 85.7 CEF 36 0.4 8818 86.0 CEFH 4 0.0 8822 86.1 CEFHlLNP 2 0.0 8824 86.1 CEFHL 1 0.0 8825 86.1 CEFHLP 1 0.0 8826 86.1 CEFl 1 0.0 8827 86.1 CEFO 1 0.0 8828 86.1 CEFP 1 0.0 8829 86.1 CEFR 4 0.0 8833 86.2 CEH 10 0.1 8843 86.3 CEHP 1 0.0 8844 86.3 CEl 9 0.1 8853 86.4 CElNU 1 0.0 8854 86.4 CELN 1 0.0 8855 86.4 CEN 2 0.0 8857 86.4 CENP 2 0.0 8859 86.4 -CER 1 0.0 8860 86.4 CEU 2 0.0 8862 86.5 CF 267 2.6 9129 89.1 CFH 30 0.3 9159 89.3
---------------------------------------------------------
95
Very Small Ground Water Systems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
CFHI 3 0.0 9162 89.4 CFHL 1 0.0 9163 89.4 CFHLO 1 0.0 9164 89.4 CFHN 2 0.0 9166 89.4 CFHNO 40 0.4 9206 89.8 CFHP 5 0.0 9211 89.9 CFI 5 0.0 9216 89.9 CFIL 1 0.0 9217 89.9 CFL 11 0.1 9228 90.0 CFLNR 1 0.0 9229 90.0 CFN 5 0.0 9234 90.1 CFNR 1 0.0 9235 90.1 CFO 4 0 .. 0 9239 90.1 CFP 12 0.1 9251 90.2 CFR 1 0.0 9252 90.3 CFU 3 0.0 9255 90.3 CH 374 3.6 9629 93.9 CHI 26 0.3 9655 94.2 CHIL 1 0.0 9656 94.2 CHL 2 0.0 9658 94.2 CHN 1 0.0 9659 94.2 CHP 1 0.0 9660 94.2 CHR 1 0.0 9661 94.2 CI 142 1.4 9803 95.6 CIL 1 0.0 9804 95.6 CL 19 0.2 9823 95.8 CLP 1 0.0 9824 95.8 CN 19 0.2 9843 96.0 CP 1 0.0 9844 96.0 CR 8 0.1 9852 96 .1 CU 3 0.0 9855 96.1 E 110 1.1 9965 97.2 ECAP 3 0.0 9968 97.2 EF 8 0.1 9976 97.3 EFP 10 0.1 9986 97.4 EH 2 0.0 9988 97.4 EHU 1 0.0 9989 97.4 EI 2 0.0 9991 97.5 EN 2 0.0 9993 97.5 EP 8 0.1 10001 97.6 ER 2 0.0 10003 97.6 EU 2 0.0 10005 97.6 F 108 1.1 10113 98.7 FH 3 0.0 10116 98.7 FHL 1 0.0 10117 98.7 FHP 1 0.0 10118 98.7 FL 3 0.0 10121 98.7 FN 1 0.0 10122 98.7 FP 1 0.0 10123 98.8 FU 2 0.0 10125 98.8 H 41 0.4 10166 99.2 HN 1 0.0 10167 99.2 HP 9 0.1 10176 99.3 I 10 0.1 10186 99.4 L 25 0.2 10211 99.6 N 9 0.1 10220 99.7 NP 2 0.0 10222 99.7 0 5 0.0 10227 99.8 .. OU 1 0.0 10228 99.8 R 5 0.0 10233 99.8 U 18 0.2 10251 100.0
---------------------------------------------------------
96
Very Small Surface Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
AC 3 0.4 3 0.4 ACEFlP 1 0.1 4 0.5 ACF 2 0.3 6 0.8 ACFLP 1 0.1 7 0.9 ACFN 1 0.1 8 1.0 ACH 1 0.1 9 1.1 AFHP 2 0.3 11 1.4 AFP 8 1.0 19 2.4 AP 2 0.3 21 2.6 C 251 31.6 272 34.2 CE 2 0.3 274 34.5 CEF 3 0.4 277 34.8 CEFLNP 1 0.1. 278 35.0 CEHP 1 0.1 279 35.1 CENO 1 0.1 280 35.2 CF 278 35.0 558 70.2 CFH 41 5.2 599 75.3 CFHl 1 0.1 600 75.5 CFHlN 2 0.3 602 75.7 CFHlR 1 0.1 603 75.8 CFHL 5 0.6 608 76.5 CFHN 9 1.1 617 77.6 CFHNO 1 0.1 618 77.7 CFHNP 1 0.1 619 77.9 CFHO 1 0.1 620 78.0 CFl 5 0.6 625 78.6 CFlL 1 0.1 626 78.7 CFlN 1 0.1 627 78.9 CFL 14 1.8 641 80.6 CFLN 1 0.1 642 80.8 CFN 10 1.3 652 82.0 CFNO 1 0.1 653 82.1 CFO 1 0.1 654 82.3 CFR 1 0.1 655 82.4 CFU 1 0.1 656 82.5 CH 7 0.9 663 83.4 CHLN 1 0.1 664 83.5 Cl 4 0.5 668 84.0 CL 1 0.1 669 84.2 CU 1 0.1 670 84.3 EFNORU 1 0.1 671 84.4 EFRU 1 0.1 672 84.5 ENOR 1 0.1 673 84.7 F 94 11.8 767 96.5 FH 5 0.6 772 97.1 FHL 3 0.4 775 97.5 FHLP 1 0.1 776 97.6 FHNP 3 0.4 779 98.0 Fl 2 0.3 781 98.2 FlU 1 0.1 782 98.4 FU 3 0.4 785 98.7 H 1 0.1 786 98.9 L 1 0.1 787 99.0 N 1 0.1 788 99.1 NOR 1 0.1 789 99.2 0 2 0.3 791 99.5 RU 2 0.3 793 99.7 U 2 0.3 795 100.0
---------------------------------------------------------
97
Small Ground Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
A 4 0.1 4 0.1 AC 227 4.4 231 4.5 ACE 8 0.2 239 4.7 ACEF 21 0.4 260 5.1 ACEFH 3 0.1 263 5.1 ACEFHL 1 0.0 264 5.2 ACEFHP 1 0.0 265 5.2 ACEFI 5 0.1 270 5.3 ACEFIP 2 0.0 272 5.3 ACEFL 1 0.0 273 5.3 ACEH 1 0.0 274 5.4 ACEHI 1 0.0 275 5.4 ACEN 1 0.0 276 5.4 ACEP 4 0.1 280 5.5 ACF 122 2.4 402 7.9 ACFH 53 1.0 455 8.9 ACFHI 2 0.0 457 8.9 ACFHIL 1 0.0 458 8.9 ACFHL 9 0.2 467 9.1 ACFHP 1 0.0 468 9.1 ACFHR 3 0.1 471 9.2 ACFI 12 0.2 483 9.4 ACFIL 1 0.0 484 9.5 ACFL 19 0.4 503 9.8 ACFLR 1 0.0 504 9.8 ACFR 3 0.1 507 9.9 ACH 81 1.6 588 11.5 ACHI 2 0.0 590 11.5 ACHLR 1 0.0 591 11.5 ACHN 1 0.0 592 11.6 ACHR 11 0.2 603 11.8 ACI 11 0.2 614 12.0 ACIL 2 0.0 616 12.0 ACL 6 0.1 622 12.2 ACN 1 0.0 623 12.2 AEF 4 0.1 627 12.3 AEFI 1 0.0 628 12.3 AEFL 1 0.0 629 12.3 AF 28 0.5 657 12.8 AFH 1 0.0 658 12.9 AFHP 24 0.5 682 13.3 AFP 47 0.9 729 14.2 AL 1 0.0 730 14.3 AP 15 0.3 745 14.6 C 3394 66.3 4139 80.9 CE 23 0.4 4162 81.3 CEF 43 0.8 4205 82.2 CEFHP 1 0.0 4206 82.2 CEFI 1 0.0 4207 82.2 CEFL 2 0.0 4209 82.2 CEFO 1 0.0 4210 82.3 CEFP 3 0.1 4213 82.3 CEH 8 0.2 4221 82.5 CEHIN 1 0.0 4222 82.5 CEI 5 0.1 4227 82.6 CEP 1 0.0 4228 82.6 CF 165 3.2 4393 85.8 CFH 47 0.9 4440 86.8 J"' ,,~
CFHI 1 0.0 4441 86.8 CFHIL 3 0.1 4444 86.8
---------------------------------------------------------
98
Small Ground Water SYstems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
CFHIP 1 0.0 4445 CFHL 8 0.2 4453 CFHLN 1 0.0 4454 CFHLP 1 0.0 4455 CFHNO 6 0.1 4461 CFHP 17 0.3 4478 CFHR 1 0.0 4479 CFI 11 0.2 4490 CFIL 4 0.1 4494 CFIP 3 0.1 4497 CFL 42 0.8 4539 CFLN 1 0.0 4540 CFN 3 0.1 4543 CFP 18 0.4 4561 CFR 3 0.1 4564 CH 215 4.2 4779 CHI 24 0.5 4803 CHL 3 0.1 4806 CHN 1 0.0 4807 CHR 1 0.0 4808 CI 132 2.6 4940 CIL 1 0.0 4941 CIN 1 0.0 4942 CIP 1 0.0 4943 CL 43 0.8 4986 CLP 2 0.0 4988 CN 3 0.1 4991 CNP 1 0.0 4992 CO 1 0.0 4993 CP 1 0.0 4994 CR 5 0.1 4999 E 3 0.1 5002 ECAP 11 0.2 5013 EFP 5 0.1 5018 EI 1 0.0 5019 EP 3 0.1 5022 F 12 0.2 5034 FH 2 0.0 5036 FHI 1 0.0 5037 FL 2 0.0 5039 FP 1 0.0 5040 H 13 0.3 5053 HL 1 0.0 5054 HP 1 0.0 5055 I 17 0.3 5072 IL 1 0.0 5073 L 39 0.8 5112 LP 1 0.0 5113 0 2 0.0 5115 R 3 0.1 5118
Small Surface Water Systems Treatment Cumulative
Combination Frequency Percent Frequency
AC 7 0.5 7 ACEFIP 7 0.5 14 ACEFLP 1 0.1 15 ACF 12 0.8 27
86.9 87.0 87.0 87.0 87.2 87.5 87.5 87.7 87.8 87.9 88.7 88.7 88.8 89.1 89.2 93.4 93.8 93.9 93.9 93.9 96.5 96.5 96.6 96.6 97.4 97.5 97.5 97.5 97.6 97.6 97.7 97.7 97.9 98.0 98.1 98.1 98.4 98.4 98.4 98.5 98.5 98.7 98.7 98.8 99.1 99.1 99.9 99.9 99.9
100.0
Cumulative Percent
0.5 0.9 1.0 1.8
L
---------------------------------------------------------
99
Small Surface Water SYstems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
ACFH 9 0.6 36 2.4 ACFHI 1 0.1 37 2.4 ACFHL 4 0.3 41 2.7 ACFHN 3 0.2 44 2.9 ACFHNP 2 0.1 46 3.0 ACFI 1 0.1 47 3.1 ACFILNP 2 0.1 49 3.2 ACFIN 1 0.1 50 3.3 ACFL 2 0.1 52 3.4 ACFN 2 0.1 54 3.6 ACH 1 0.1 55 3.6 ACI 1 0.1 56 3.7 AFHP 29 1.9 85 5.6 AFP 16 1.1 101 6.6 AP 1 0.1 102 6.7 C 423 27.8 525 34.6 CE 4 0.3 529 34.8 CEF 7 0.5 536 35.3 CEFH 1 0.1 537 35.4 CEFHN 1 0.1 538 35.4 ....
CEFINP 1 0.1 539 35.5 CEFL 1 0.1 540 35.5 CEFLNP 4 0.3 544 35.8 CEFLP 1 0.1 545 35.9 CEFN 2 0.1 547 36.0 CEI 1 0.1 548 36.1 CELN 2 0.1 550 36.2 CF 332 21. 9 882 58.1 CFH 152 10.0 1034 68.1 CFHI 18 1.2 1052 69.3 CFHILP 1 0.1 1053 69.3 CFHIN 5 0.3 1058 69.7 CFHL 27 1.8 1085 71.4 CFHLN 9 0.6 1094 72.0 CFHLP 1 0.1 1095 72.1 CFHN 36 2.4 1131 74.5 CFHNP 1 0.1 1132 74.5 CFHP 2 0.1 1134 74.7 CFI 40 2.6 1174 77.3 CFIL 10 0.7 1184 77.9 CFILN 2 0.1 1186 78.1 CFIN 6 0.4 1192 78.5 CFL 39 2.6 1231 81. 0 CFLN 20 1.3 1251 82.4 CFN 29 1.9 1280 84.3 CFNP 1 0.1 1281 84.3 CFU 1 0.1 1282 84.4 CH 20 1.3 1302 85.7 CHI 5 0.3 1307 86.0 CHL 5 0.3 1312 86.4 CHLP 2 0.1 1314 86.5 CHNP 1 0.1 1315 86.6 CI 11 0.7 1326 87.3 CIL 1 0.1 1327 87.4 CL CLP
9 4
0.6 0.3
1336 1340
88.0 88.2 -eN
CO 3 1
0.2 0.1
1343 1344
88.4 88.5 ."
ECAP 3 0.2 1347 88.7 F 124 8.2 1471 96.8 FH 4 0.3 1475 97.1
---------------------------------------------------------
100
Small Surface Water Systems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
FHL 2 0.1 1477 97.2 FHLP 4 0.3 1481 97.5 FHNP 11 0.7 1492 98.2 FL 2 0.1 1494 98.4 FNP 5 0.3 1499 98.7 H 11 0.7 1510 99.4 HI 2 0.1 1512 99.5 HP 1 0.1 1513 99.6 I 1 0.1 1514 99.7 L 5 0.3 1519 100.0
Medium Ground Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
A 2 0.2 2 0.2 AC 83 6.4 85 6.5 ACE 5 0.4 90 6.9" ACEF 2 0.2 92 7.0 ACEFH 2 0.2 94 7.2 ACEFI 2 0.2 96 7.4 ACEFIP 1 0.1 97 7.4 ACEFIPR 1 0.1 98 7.5 ACEFLP 1 0.1 99 7.6 ACEI 2 0.2 101 7.7 ACF 46 3.5 147 11.3 ACFH 26 2.0 173 13.2 ACFHIL 1 0.1 174 13.3 ACFHL 3 0.2 177 13 .6 ACFHLR 1 0.1 178 13.6 ACFHN 1 0.1 179 13.7 ACFHP 3 0.2 182 13.9 ACFHR 1 0.1 183 14.0 ACFI 14 1.1 197 15.1 ACFL 11 0.8 208 15.9 ACFR 1 0.1 209 16.0 ACH 28 2.1 237 18.1 ACHI 4 0.3 241 18.5 ACHL 1 0.1 242 18.5 ACI 3 0.2 245 18.8 ACL 4 0.3 249 19.1 ACN 2 0.2 251 19.2 AEF 1 0.1 252 19.3 AF 2 0.2 254 19.4 AFHP 4 0.3 258 19.8 AFI 1 0.1 259 19.8 AFP 8 0.6 267 20.4 AP 2 0.2 269 20.6 C 752 57.6 1021 78.2 CE 12 0.9 1033 79.1 CEF 6 0.5 1039 79.6 CEFH 3 0.2 1042 79.8 CEFHL 1 0.1 1043 79.9 CEFHP 2 0.2 1045 80.0 CEFI 1 0.1 1046 80.1 CEFIP 3 0.2 1049 80.3 CEFP 2 0.2 1051 80.5 CEH 3 0.2 1054 80.7 CEHP 1 0.1 1055 80.8
-
./
---------------------------------------------------------
---------------------------------------------------------
101
Medium Ground Water SYstems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
CF 48 3.7 1103 84.5 CFH 17 1.3 1120 85.8 CFHI 4 0.3 1124 86.1 CFHIL 2 0.2 1126 86.2 CFHIP 2 0.2 1128 86.4 CFHL 6 0.5 1134 86.8 CFHNO 1 0.1 1135 86.9 CFHP 4 0.3 1139 87.2 CFI 2 0.2 1141 87.4 CFIP 1 0.1 1142 87.4 CFL 13 1.0 1155 88.4 CFLN 1 0.1 1156 88.5 CFLP 1 0.1 1157 88.6 CFN 1 0.1 1158 88.7 CFO 2 0.2 1160 88.8 CFP 7 0.5 1167 89.4 CFR 1 0.1 1168 89.4 CH 45 3.4 1213 92.9 CHI 8 0.6 1221 93.5 CHIL 1 0.1 1222 93 .--6 CHN 1 0.1 1223 93.6 CI 43 3.3 1266 96.9 CIL 2 0.2 1268 97.1 CL 18 1.4 1286 98.5 CP 1 0.1 1287 98.5 ECAP 2 0.2 1289 98.7 F 4 0.3 1293 99.0 FHNP 1 0.1 1294 99.1 H 3 0.2 1297 99.3 HI 2 0.2 1299 99.5 I 1 0.1 1300 99.5 L 5 0.4 1305 99.9 LP 1 0.1 1306 100.0
Medium Surface Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
AC 4 0.4 4 0.4 ACE 1 0.1 5 0.5 ACEFH 1 0.1 6 0.6 ACEFHINP 2 0.2 8 0.8 ACEFIP 10 1.0 18 1.8 ACEFLP 1 0.1 19 1.9 ACEP 1 0.1 20 2.0 ACF 7 0.7 27 2.8 ACFH 11 1.1 38 3.9 ACFHI 2 0.2 40 4.1 ACFHIL 1 0.1 41 4.2 ACFHIP 1 0.1 42 4.3 ACFHL 1 0.1 43 4.4 ACFHLN 3 0.3 46 4.7 ACFHP 1 0.1 54 5.5 ACFI 1 0.1 55 5.6 ACFIN 3 0.3 58 5.9 ACFL 1 0.1 59 6.0 ACFN 2 0.2 61 6.2 ACHI 3 0.3 64 6.5 AFHP 21 2.1 85 8.7
-.
---------------------------------------------------------
102
Medium Surface Water Systems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
ACFHLP ACFHN
2 4
0.2 0.4
48 52
4.9 5.3
r. ~
ACFHNP 1 0.1 53 5.4 ,
AFP C CE
7 194
2
0.7 19.8 0.2
92 286 288
9.4 29.2 29.4
l I I
CEF CEFH
3 1
0.3 0.1
291 292
29.7 29.8 (
CEFHL 3 0.3 295 30.1 CEFHLN 2 0.2 297 30.3 CEFILN 1 0.1 298 30.4 CEFINP 2 0.2 300 30.6 CEFL 1 0.1 301 30.7 CEFLNP 4 0.4 305 31.1 CEH 1 0.1 306 31.2 CEHP 1 0.1 307 31.3 CF 168 17.1 475 48.5 CFH 128 13 .1 603 61.5 CFHI 25 2.6 628 64.1 CFHIL 2 0.2 630 64,.3 CFHIN 13 1.3 643 65.6 CFHL 14 1.4 657 67.0 CFHLN 6 0.6 663 67.7 CFHN 35 3.6 698 71.2 CFHNP 1 0.1 699 71.3 CFHP 2 0.2 701 71. 5 CFHR 1 0.1 702 71.6 CFI 33 3.4 735 75.0 CFIL 3 0.3 738 75.3 CFILN 1 0.1 739 75.4 CFIN 9 0.9 748 76.3 CFINP 1 0.1 749 76.4 CFL 17 1.7 766 78.2 CFLN 8 0.8 774 79.0 CFN 31 3.2 805 82.1 CFO 1 0.1 806 82.2 CH 23 2.3 829 84.6 CHI 6 0.6 835 85.2 CHL 4 0.4 839 85.6 CHN 1 0.1 840 85.7 CHNP 1 0.1 841 85.8 CI 9 0.9 850 86.7 CIL 2 0.2 852 86.9 CILP 1 0.1 853 87.0 CIN 1 0.1 854 87.1 CINP 1 0.1 855 87.2 CL 9 0.9 864 88.2 CLP CN
2 2
0.2 0.2
866 868
88.4 88.6
j
E 1 0.1 869 88.7 ECAP 4 0.4 873 89.1 F 63 6.4 936 95.5 FH 4 0.4 940 95.9 FHL 1 0.1 941 96.0 FHN 1 0.1 942 96.1 FHNP 17 1.7 959 97.9 -FI 2 0.2 961 98.1 FL 1 0.1 962 98.2 ....~,
FNP 5 0.5 967 98.7 H 6 0.6 973 99.3 HN 3 0.3 976 99.6
---------------------------------------------------------
103
Medium Surface Water SYstems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
HP 2 0.2 978 99.8 I 1 0.1 979 99.9 L 1 0.1 980 100.0
Large Ground Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
A 1 0.1 1 0.1 AC 76 10.3 77 10.4 ACE 2 0.3 79 10.7 ACEF 2 0.3 81 11. 0 ACEFH 1 0.1 82 11.1 ACEFIP 3 0.4 85 1l.5 ACEFL 1 0.1 86 11. 7 ACEH 2 0.3 88 11. 9 ACEP 1 0.1 89 12.1 ACER 1 0.1 90 12.2 ACF 19 2.6 109 14.8 ACFH ACFHI
29 6
3.9 0.8
138 144
18.} 19.5
ACFHIN 1 0.1 145 19.6 ACFHL 4 0.5 149 20.2 ACFHLR 4 0.5 153 20.7 ACFHP 1 0.1 154 20.9 ACFHR 1 0.1 155 21. 0 ACFI 9 1.2 164 22.2 ACFIL 1 0.1 165 22.4 ACFILN 1 0.1 166 22.5 ACFIN 1 0.1 167 22.6 ACFIP 1 0.1 168 22.8 ACFL 21 2.8 189 25.6 ACFN 1 0.1 190 25.7 ACH 25 3.4 215 29.1 ACHI 2 0.3 217 29.4 ACHL 1 0.1 218 29.5 ACHN 1 0.1 219 29.7 ACHR 4 0.5 223 30.2 ACI 5 0.7 228 30.9 ACIL 1 0.1 229 31. 0 ACIN 1 0.1 230 31.2 ACL 3 0.4 233 31.6 ACN 4 0.5 237 32.1 AF 1 0.1 238 32.2 AFHLR 1 0.1 239 32.4 AFHP 2 0.3 241 32.7 AFP 8 1.1 249 33.7 AH 1 0.1 250 33.9 AP 1 0.1 251 34.0 C 300 40.7 551 74.7 CE 5 0.7 556 75.3 CEF 3 0.4 559 75.7 CEFH 2 0.3 561 76.0 CEFHI 1 0.1 562 7.6.2 CEFI 2 0.3 564 76.4 CEFIR 1 0.1 565 76.6 CEHI 1 0.1 566 76.7 CF 17 2.3 583 79.0 CFH 11 1.5 594 80.5
-...
---------------------------------------------------------
---------------------------------------------------------
104
Large Ground Water Systems (continued) Treatment Cumulative Cumulative
Coriiliination Frequency Percent Frequency Percent
CFHI 3 0.4 597 80.9 CFHIL 2 0.3 599 81.2 CFHIO 1 0.1 600 81.3 CFHIP 2 0.3 602 81.6 CFHL 4 0.5 606 82:1 CFHN 4 0.5 610 82.7 CFHP 3 0.4 613 83.1 CFI 1 0.1 614 83.2 CFILNP 1 0.1 615 83.3 CFL 19 2.6 634 85.9 CFLN 2 0.3 636 86.2 CFN 1 0.1 637 86.3 CFO 1 0.1 638 86.4 CFP 2 0.3 640 86.7 CH 33 4.5 673 91.2 CHI 4 0.5 677 91. 7 CHL 1 0.1 678 91. 9 CI 21 2.8 699 94.7 CIL 3 0.4 702 95.1 CL 18 2.4 720 97.6 CLO 1 0.1 721 97.7 CLR 2 0.3 723 98. Go CN 2 0.3 725 98.2 CP 1 0.1 726 98.4 CR 1 0.1 727 98.5 ECAP 1 0.1 728 98.6 F 2 0.3 730 98.9 FH 1 0.1 731 99.1 FHNP 1 0.1 732 99.2 H 1 0.1 733 99.3 HI 1 0.1 734 99.5 HP 1 0.1 735 99.6 I 1 0.1 736 99.7 L 1 0.1 737 99.9 R 1 0.1 738 100.0
Large Surface Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
AC 6 0.6 6 0.6 ACE 1 0.1 7 0.7 ACEFH 1 0.1 8 0.8 ACEFIP 11 1.1 19 1.9 ACEFN 1 0.1 20 2.0 ACEFP 1 0.1 21 2.1 ACEH 1 0.1 22 2.2 ACF 19 1.9 41 4.1 ACFH 12 1.2 53 5.3 ACFHI 1 0.1 54 5.4 ACFHILN 1 0.1 55 5.5 ACFHIN 3 0.3 58 5.8 ACFHIO ACFHL
1 1
0.1 0.1
59 60
5.9 6.0 -ACFHLNP 3 0.3 63 6.3
ACFHN 9 0.9 72 7.2 " .. ACFHOP 1 0.1 73 7.3 ACFHP 1 0.1 74 7.4 ACFI 2 0.2 76 7.6 l
( I i
---------------------------------------------------------
105
Large Surface Water SYstems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
ACFILNP 1 0.1 77 7.7 ACFIN 2 0.2 79 7.9 ACFL 1 0.1 80 8.0 ACFLN 2 0.2 82 8.2 ACFLO 1 0.1 83 8.4 ACFN 2 0.2 85 8.6 ACH 2 0.2 87 8.8 ACHI 2 0.2 89 9.0 ACHN 1 0.1 90 9.1 AFHP 14 1.4 104 10.5 AFP 6 0.6 110 11.1 AI 1 0.1 111 11. 2 AP 1 0.1 112 11. 3 C 178 17.9 290 29.2 CE 1 0.1 291 29.3 CEFH 1 0.1 292 29.4 CEFHLP 1 0.1 293 29.5 CEFHN 2 0.2 295 29.7 CEFHNP 1 0.1 296 29.8 CEFINP 21 2.1 317 31.9 CEFLNP 8 0.8 325 32.7 CEFN 2 0.2 327 32.9 CEHI 1 0.1 328 33.0CELN 1 0.1 329 33.1 CF 114 11.5 443 44.6 CFH 113 11.4 556 55.9 CFHI 38 3.8 594 59.8 CFHIL 3 0.3 597 60.1 CFHILN 3 0.3 600 60.4 CFHIN 25 2.5 625 62.9 CFHIP 1 0.1 626 63.0 CFHL 11 1.1 637 64.1 CFHLN 3 0.3 640 64.4 CFHLP 1 0.1 641 64.5 CFHLR 1 0.1 642 64.6 CFHN 45 4.5 687 69.1 CFHNP 1 0.1 688 69.2 CFHO 3 0.3 691 69.5 CFHP 4 0.4 695 69.9 CFHR 1 0.1 696 70.0 CFI 23 2.3 719 72.3 CFIL 4 0.4 723 72.7 CFILN 5 0.5 728 73.2 CFILNP 1 0.1 729 73.3 CFILP 3 0.3 732 73.6 CFIN 17 1.7 749 75.4 CFIP 1 0.1 750 75.5 CFL 6 0.6 756 76.1 CFLN 10 1.0 766 77.1 CFLNP 1 0.1 767 77.2 CFN 29 2.9 796 80.1 CFO 1 0.1 797 80.2 CH 13 1.3 810 81. 5 CHI 4 0.4 814 81. 9 CHL CHN
2 1
0.2 0.1
816 817
82.1 82.2
CI 9 0.9 826 83.1 CIL CILN
1 1
0.1 0.1
827 828
83.2 83.3
",
CIN 3 0.3 831 83.6 CINP 3 0.3 834 83.9
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---------------------------------------------------------
---------------------------------------------------------
106
Large Surface Water SYstems (continued) f I
Treatment Cumulative Cumulative Combination Frequency Percent Frequency Percent f· --------------------------------------------------------
CL 17 1.7 851 85.6 CLN 2 0.2 853 85.8 I CLP 1 0.1 854 85.9
j •
CN 1 0.1 855 86.0 ECAP 6 0.6 861 86.6 r F 84 8.5 945 95.1 I
FH 1 0.1 946 95.2 FHLP 6 0.6 952 95.8 JFHNP 22 2.2 974 98.0 FNP 8 0.8 982 98.8 FO 1 0.1 983 98.9 H 3 0.3 986 99.2 HN 1 0.1 987 99.3 I 1 0.1 988 99.4 • N 2 0.2 990 99.6 NP 1 0.1 991 99.7 r 0 1 0.1 992 99.8
I
OP 1 0.1 993 99.9
IrP 1 0.1 994 100.0
I
Very Large Ground Water Systems I,I
'_Treatment Cumulative Cumulative Combination Frequency Percent Frequency Percent
AC 4 9.5 4 9.5 ACFH 1 2.4 5 11.9 ACFHl 1 2.4 6 14.3 ACFHL 1 2.4 7 16.7 ,.ACFHN 1 2.4 8 19.0 ACFl 1 2.4 9 21.4 iACFL 2 4.8 11 26.2
IACH 3 7.1 14 33.3 ACHN 1 2.4 15 35.7 I C 12 28.6 27 64.3 CFH 2 4.8 29 69.0 CFHl 1 2.4 30 71.4 CFHL 1 2.4 31 73.8 CFL 4 9.5 35 83.3 CH 1 2.4 36 85.7 ClL 1 2.4 37 88.1 CL 1 2.4 38 90.5 CN 1 2.4 39 92.9 F 3 7.1 42 100.0
Very Large Surface Water Systems Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
AC 1 0.6 1 0.6 ACF 4 2.5 5 3.2 ACFH 5 3.2 10 6.3 ACFHl 1 0.6 11 7.0 .-ACFHlN 2 1.3 13 8.2 ACFHlNP 1 0.6 14 8.9 "" .......
ACFHN 1 0.6 15 9.5 ACFLN 1 0.6 16 10.1 ACFN 1 0.6 17 10.8 .\. ,
---------------------------------------------------------
107
Very Large Surface Water Systems (continued) Treatment Cumulative Cumulative
Combination Frequency Percent Frequency Percent
ACFO ACHl AFHP C CEFHlN CEFlNP CEFLN CEFLNP CF CFH CFHl CFHlLNP CFHlN CFHlNP CFHLN CFHLNP CFHN CFHP CFl CFlLN CFlN CFL CFN CFO CH ClL ClN CL EFNO F FHLP FHNP FlLP FNP
1 1 1
10 1 2 1 3
21 20
5 1 4 2 2 1
11 1 1 1 4 3 7 1 3 1 1 2 1
18 1 7 1 1
0.6 0.6 0.6 6.3 0.6 1.3 0.6 1.9
13.3 12.7 3.2 0.6 2.5 1.3 1.3 0.6 7.0 0.6 0.6 0.6 2.5 1.9 4.4 0.6 1.9 0.6 0.6 1.3 0.6
11.4 0.6 4.4 0.6 0.6
18 19 20 30 31 33 34 37 58 78 83 84 88 90 92 93
104 105 106 107 111 114 121 122 125 126 127 129 130 148 149 156 157 158
11.4 12.0 12.7 19.0 19.6 20.9 21.5 23.4 36.7 49.4 52.5 53.2 55.7 57.0 58.2 58.9 65.8 66.5 67.1 67.7 70.3 72.2 76.6 77.2 79.1 79.7 " 80.4 81.6 82.3 93.7 94.3 98.7 99.4
100.0
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• OTHER AoRoMoEo RESEARCH BULLETINS
No. 96-09
No. 96-10
No. 96-11
No. 96-12
No. 96-13
No. 96-14
No. 96-15
No. 96-16
The Feasibility of a Mid-Hudson Valley Wholesale Fresh Product Facility: A Buyer Assessment
Impact of National Dairy Advertising on Dairy Markets, 198495
Dairy Farm Management Business Summary New York State 1995
A Spatial Equilibrium Model for Imperfectly Competitive Milk Markets
Developing a Farm Plan to Address Water Quality and Farm Business Objectives: A Framework for Planning
An Economic Analysis of Generic Egg Advertising in California, 19851995
An Ex Post Evaluation of Generic Egg Advertising in the U.S.
Identifying Consumer Characteristics Associated with Japanese Preferences Towards Milk Products
Craig Robert Kreider Edward W. McLaughlin
Harry M. Kaiser
Stuart F. Smith Wayne A. Knoblauch Linda D. Putnam
Tsunemasa Kawaguchi Nobuhiro Suzuki Harry Kaiser
"
John J. Hanchar Robert A. Milligan Wayne A. Knoblauch
Todd M.Schmit J. Carlos Reberte Harry M. Kaiser
J. Carlos Reberte Todd M. Schmit Harry M. Kaiser
Yasuhito Watanabe Nobuhiro Suzuki Harry M. Kaiser
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I ~